In a 12-week trial conducted in 275 patients suffering from irritable bowel syndrome, 71% of those taking 10 g of psyllium daily reported moderate-intensity flatulence. The figure seems high, until you look at the next column: 78% on rice flour placebo. The entire psyllium profile comes down to this difference: a fiber that is very well studied, fairly well tolerated, with rare but sometimes serious risks, the main one being how you take it: without enough water, its gel can block the esophagus or intestine.
This guide brings together what studies identified via PubMed show, from gas to obstruction, from allergies to drug interactions, classifying each risk as established, rare, theoretical, or a myth, then provides rules for proper use and warning signs requiring you to stop or consult a doctor.
What is established : gas, bloating and digestive discomfort are the most common effects, often just as frequent as placebo in trials, and psyllium lowers blood sugar in type 2 diabetics by 0.97 HbA1c points in a meta-analysis. Regarding medications, a small study in 8 volunteers suggests that psyllium taken at the same time may delay the absorption of levothyroxine (240 minutes instead of 180, at median), without a detectable decrease in the amount absorbed.
What is rare, but serious : obstruction of the esophagus or intestine, described in isolated cases in people who drank too little, exceeded the dose, or already had a swallowing disorder. In those who inhale the powder at work, sensitization is common, up to 26% of workers carrying IgE antibodies in one factory; after ingestion, allergy is exceptional, but sometimes severe, especially in people already sensitized. The signal regarding colon polyps remains uncertain.
- Blonde psyllium: what it is and why it may cause discomfort
- Gas, bloating, discomfort: the most frequent effects
- Obstruction of the esophagus or intestine
- True contraindications
- Konjac and other swelling fibers: the same water rule
- Allergy: occupational asthma and anaphylaxis
- Medications: what interaction studies measure
- Diabetes: an effect on blood sugar to anticipate
- Minerals: a concern mainly theoretical
- Pregnancy, children, elderly people
- Common myths and uncertain signals
- The risk table and rules for proper use
- Frequently asked questions
Blond psyllium: what it is and why it can cause problems
Blond psyllium is the husk, that is the coating, of Plantago ovata seeds, ground into powder. It is a soluble fiber that forms a viscous gel when in contact with water. In the small intestine, the viscosity of this gel explains its measured effects on cholesterol and blood sugar. In the colon, it resists fermentation by bacteria, remains present even in stools, and retains its ability to hold water, making them more voluminous and softer. These mechanisms are described in two reviews, at least one of which is signed by a researcher employed by an industrial manufacturer that markets psyllium. Hence its main risks: a gel lacking water can become a blockage, and a gel that traps a medication can delay its absorption.
Overall tolerance is reassuring. Authors of a meta-analysis of 8 trials (384 people on psyllium, 272 on placebo), who measured a 7% reduction in LDL cholesterol with 10.2 g per day combined with a low-fat diet, pooled safety data from 19 studies lasting 6 weeks to 6 months: psyllium is well tolerated. In those over 65, a review of 23 trials on laxatives finds comparable side effects between treated and control groups, and reasonably safe use over 3 months. Its benefits are detailed in our guide on blond psyllium.
Established : repeatedly observed in trials or studies. Rare : real, but described mainly in isolated cases, with unknown frequency. Theoretical : plausible based on mechanism, animal data, or small studies, without demonstrated clinical consequence. Misconception : belief that the data do not support.
Gas, bloating, discomfort: the most frequent effects
The most detailed controlled trial on digestive disorders was conducted in the Netherlands, in 275 adults aged 18 to 65 suffering from irritable bowel syndrome: 10 g of psyllium, wheat bran, or rice flour per day for 12 weeks, mixed into meals, with instructions to drink plenty of water. These patients already had digestive symptoms, hence the high rates across the board.
| Moderate effect, more than half the time | Psyllium | Placebo |
|---|---|---|
| Flatulence | 71% | 78% |
| Diarrhea | 62% | 71% |
| Constipation | 62% | 69% |
| Nausea or vomiting | 14% | 20% |
| Difficulty swallowing | 11% | 13% |
| At least one moderate side effect | 74% | 66% |
| Discontinuation due to intolerance | 7 patients out of 85 | 9 patients out of 93 |
Effect by effect, the differences were not statistically significant, and no serious adverse effects were reported. Wheat bran was less well tolerated: 18 patients discontinued it due to intolerance, twice as many as in the other groups. Overall, 40% of patients left the trial before completion, across all groups.
In 275 patients with irritable bowel syndrome followed in general practice, 10 g of psyllium per day provided greater relief than placebo during the first month, 57% responders versus 35%, and in the second month, 59% versus 41%. Flatulence, diarrhea and constipation were equally frequent with psyllium as with placebo, with no serious adverse effects.
Bijkerk CJ, de Wit NJ, Muris JW, et al. BMJ 2009;339:b3154. DOI: 10.1136/bmj.b3154
Why relatively little gas? Because psyllium is poorly fermented by the microbiota, unlike inulin. In a 2022 meta-analysis on chronic constipation, 16 trials and 1,251 adults, fiber increases flatulence with an effect size of 0.80 (by convention, 0.2 is a small effect, 0.5 moderate, 0.8 large), but 2 of the 3 relevant studies, which account for 89.9% of the result, tested inulin; regarding bloating, no difference (0.07, 4 studies). With psyllium, one trial reported abdominal pain in 2 participants (18%), versus none in the control group, and another reported 3 discontinuations for adverse effects, versus 5 among controls. The authors recommend increasing fiber gradually.
Our Organic blonde psyllium is taken at the rate of one tablespoon per day, or 5 to 10 g. Practical tip: start at the lower end of the range, around 5 g, for one week, then increase if your stomach tolerates it. Mild gas initially is expected; persistent bloating, pain, or a hard abdomen require stopping. Our guides on bloated belly and to reduce bloating help identify the cause.
Obstruction of the esophagus or intestine
Psyllium is highly hygroscopic: it retains water and swells rapidly to several times its original volume. This is why it is drunk immediately after mixing. Swallowed with too little liquid, or in a person whose esophagus or intestine empties poorly, it can form a bezoar, a compact mass that blocks the passage. A review dedicated to medication-induced bezoars lists psyllium among the products involved, most often when the motility or anatomy of the digestive tract is already impaired.
A 76-year-old man with Parkinson's disease was taking approximately 5 g of psyllium powder per day with water for constipation, and had already occasionally experienced difficulty swallowing after taking it. A few hours after one dose, discomfort appeared and worsened to the point of inability to swallow, even his saliva: the scan showed a mass of approximately 2.0 × 2.5 cm just above the stomach, removed by endoscopy after fragmentation.
Shin S, Kim JH, Mun YH, Chung HS. World J Clin Cases 2022;10(7):2336-2340. DOI: 10.12998/wjcc.v10.i7.2336
This case concerns powder, at standard dosage, with water: the powder form does not eliminate the risk when the esophagus functions poorly. Lower down, it is the intestine that can become blocked. A 21-year-old had taken psyllium husk to control his weight during a fast that prevented him from drinking during the day; arriving at the emergency room for constipation, he left with packets of 7 g twice daily, and two days later presented with incomplete intestinal obstruction, resolved without surgery by enemas. A 53-year-old man, who had confused his bowel prep solution with psyllium, had swallowed approximately 47.6 g in 6 hours, yet diluted at each dose in approximately 240 ml of water: small bowel obstruction with air in the intestinal wall (pneumatosis), managed without surgery, discharged on the fourth day.
Level: rare. These isolated cases do not allow us to calculate a frequency; those we have read all describe an aggravating factor—lack of water, overdose, or fragile digestive tract. The consequences can be serious, but prevention is simple.
Our instruction Organic blonde psyllium : a large glass of water, juice, or a smoothie, mixed immediately and consumed before it gels. In practice, at least 200 to 250 ml per dose (the levodopa study presented below dispersed 3.5 g in 200 ml of water), then drink normally throughout the day. Never dry powder or held in the mouth, no dose just before lying down, no exceeding the recommended amount. Practical tips: no study has compared different water quantities.
True contraindications
The authors of the 2022 case remind us that swallowing difficulties affect up to 77% of people with Parkinson's disease, and that anything slowing passage through the esophagus—previous digestive surgery, stricture, achalasia—favors bezoar formation. The 2018 review cites esophageal blockages in elderly people who drank little and after gastric band placement, as well as four small intestine obstructions that occurred when psyllium was used as a contrast agent for imaging, with only one requiring surgery; the authors of these cases identify small intestinal strictures as a risk factor. They recommend avoiding bulk laxatives in case of obstruction or ileus, that is, intestinal paralysis.
Swallowing disorders, regardless of cause, including Parkinson's disease. Esophageal stricture or achalasia. Gastric band or other stomach or intestinal surgery. History of obstruction, known intestinal stricture, ileus. Unexplained abdominal pain, vomiting, absence of gas and stools: these are signs of obstruction, not constipation to be treated. Difficulty swallowing during a previous dose. Children under 12 years old, for whom our psyllium is not recommended.
Konjac and other swelling fibers: the same water rule
The review on drug-induced bezoars also cites guar gum. The glucomannan, the fiber from the konjac rhizome, also strongly retains water and swells rapidly. One published case describes a 37-year-old woman who experienced delayed esophageal blockage after a weight-loss product containing glucomannan; vomiting freed her just before the planned endoscopy, and subsequent examination discovered a thin membrane in her esophagus, a risk condition according to the authors. They cite as reported adverse effects of glucomannan bloating, abdominal pain, digestive obstruction, and possible changes in medication absorption: the psyllium profile.
For our Pure Konjac, one capsule before each meal, the instructions emphasize: plenty of water is needed for the capsule to reach the stomach. This is exactly the psyllium safety rule, and the same people should seek medical advice before taking it: swallowing disorder, digestive stricture, history of obstruction. Our article on konjac and its risks details studies specific to this fiber, and our guide konjac and transit compares it to other fibers.
Allergy: occupational asthma and anaphylaxis
Psyllium allergy has been documented since the 1970s in those who inhale its dust. In a pharmaceutical factory, 27 of 64 workers packaging the husk developed rhinitis, conjunctivitis, or asthma; when dust was reduced, only one new case appeared in 24 months, and 5 similar cases were reported among healthcare workers. In a company processing psyllium, 19% of tested employees reacted to skin testing, 26% had specific IgE antibodies, and 5 of 18 workers tested by inhalation showed immediate bronchoconstriction. In a laxative factory using psyllium and senna, 7.6% of 125 workers were allergic to psyllium, and 4 (3.2%) had occupational asthma linked to one or the other.
Among staff at four long-term care hospitals where psyllium was prepared, sensitization ranged from 5% on skin testing to 12% on IgE measurement, and 4 of 6 healthcare workers tested in the laboratory reacted with bronchospasm. A 43-year-old nurse even experienced anaphylaxis preparing it, without ingesting it. More recently, a 24-year-old baker developed occupational psyllium rhinitis, which has become common in gluten-free and vegan baking. Level: Established, for repeated occupational powder exposure.
After ingestion, published cases mainly concern people already sensitized, most often nurses exposed to the powder at work. Two nurses aged 39 and 42, who had nasal and eye symptoms when distributing the product, had a generalized reaction upon swallowing it, with loss of consciousness in the second case upon re-exposure. A 38-year-old nurse experienced severe anaphylaxis with blood pressure drop 25 minutes after a bowl of psyllium cereal. A 69-year-old nurse, who had suffered from psyllium-related rhinitis and asthma for 15 years without the connection being made, eventually had anaphylaxis after ingesting it.
A 42-year-old woman died from anaphylaxis after ingesting a psyllium-based product. The associated review, from 1966 to 2002, describes well-documented hypersensitivity in healthcare workers and pharmaceutical industry employees, with respiratory symptoms on inhalation progressing to anaphylaxis on ingestion, and a clear association with atopic background.
Khalili B, Bardana EJ, Yunginger JW. Ann Allergy Asthma Immunol 2003;91(6):579-584. DOI: 10.1016/S1081-1206(10)61538-4
Level: Rare after ingestion. Isolated cases, with no known frequency. At-risk population: atopic individuals, that is, those prone to allergies, and especially those who have already experienced runny nose, itchy eyes, or respiratory discomfort when handling psyllium. Practical tip: pour the powder slowly into the liquid to minimize dust.
Medications: what interaction studies measure
The gel may retain part of a medication and alter its absorption. The actual magnitude of the effect is less clear: a 2012 review on interactions with Plantago ovata husk notes that studies are few and far between, with often variable results, showing both favorable and unfavorable effects depending on the medication. A review on laxatives concludes that bulk agents may decrease the absorption of certain minerals and medications, most often without clinical consequence.
Eight volunteers took 600 µg of levothyroxine alone, then with 3.4 g of psyllium taken simultaneously. The absorbed fraction decreased from 89% to 80%, with confidence intervals that largely overlap; peak occurred at 240 minutes instead of 180 at median, with no statistical test reported.
Chiu AC, Sherman SI. Thyroid 1998;8(8):667-671. DOI: 10.1089/thy.1998.8.667
| Medication | What was measured | Level |
|---|---|---|
| Levothyroxine | 8 volunteers, simultaneous intake: absorption from 89% to 80%; peak at 240 minutes instead of 180, without statistical test | Possible delay, single small study |
| Levodopa | 18 Parkinsonian patients, 3.5 g just before each dose for 14 days: no significant difference, smoother curves | No measured adverse effect |
| Lithium | A 1990 letter describes an interaction in one patient | Isolated case, signal to monitor |
In the levodopa trial, in patients aged 60 to 80, 3.5 g of husk in 200 ml of water just before each of the three daily doses did not significantly modify any absorption parameter; only 11% of patients had concentrations with multiple peaks, compared to 44% at baseline and 50% with placebo. For lithium, data is limited to cases: a letter published in 1990 in The Lancet reports an interaction between lithium salts and psyllium in one patient, a serious signal for a medication with a narrow therapeutic margin, but not proof. For carbamazepine, often cited, we found no human study indexed in PubMed.
Lacking data for most medications, the simplest approach is to separate doses: the instructions for our Organic Blonde Psyllium ask to take it at least 2 hours away from any medication. This is a precautionary rule, not a figure from a trial. If your treatment needs to be dosed precisely, such as lithium, levothyroxine, an anticonvulsant, or a heart medication, inform your doctor before starting.
Diabetes: an effect on blood sugar to anticipate
A meta-analysis of 35 trials, led by researchers from a company marketing psyllium and academics, shows an effect proportional to baseline blood sugar: not significant when normal, modest in prediabetes, maximal in treated type 2 diabetics, with −37.0 mg/dL fasting blood glucose and −0.97% HbA1c when psyllium was taken before meals for several weeks. The authors add that further studies are needed to determine how to combine it with blood sugar-lowering medications.
In a double-blind Iranian trial, 49 type 2 diabetics took 5.1 g of psyllium twice daily, half an hour before breakfast and dinner, in addition to their regular treatment, for 8 weeks. Fasting blood glucose and HbA1c decreased significantly, psyllium was well tolerated with no serious adverse effects, and metformin was even better tolerated digestively.
Level: theoretical, to be monitored. These publications report no severe hypoglycemia, but a drop of nearly one percentage point in HbA1c is not trivial when added to a treatment regimen. If under treatment, especially insulin or sulfonylureas, discuss it with your doctor, monitor your blood glucose for the first few weeks, and maintain a 2-hour gap with your tablets. See also our guides on high blood glucose and LDL cholesterol.
Minerals: a concern that is mainly theoretical
In a crossover trial involving 15 postmenopausal women, calcium absorption from fortified orange juice was 34.1% without fiber and 31.7% with 3.4 g of psyllium in the same meal, a non-significant difference; it reached 35.4% with cellulose (the only significant difference: psyllium versus cellulose), and the authors conclude that psyllium minimally changes calcium availability at usual doses. In 12 elderly people followed for 4 months on psyllium fiber, blood iron, iron-binding capacity, and hemoglobin did not change; only a decrease in blood calcium was noted after stopping the fiber; the authors judge that its phytates have no notable effect on mineral absorption.
Level: theoretical, weak effect. Older data and small sample sizes, but consistent findings. Practical advice: space your iron, calcium, or magnesium supplements as you would a medication.
Pregnancy, children, elderly persons
Pregnancy. The Cochrane review on constipation during pregnancy was able to analyze only 2 trials, involving 180 women. In one, fiber supplementation increased stool frequency by 2.24 per week in 40 women; in the other, stimulant laxatives provided more relief than bulk-forming laxatives, at the cost of more abdominal discomfort. No usable data existed on allergic reactions or dehydration, and the authors judge the evidence insufficient to assess the safety of these treatments. Data are lacking: during pregnancy and breastfeeding, consult your doctor or midwife.
Children. In an Italian trial of 100 children averaging 6.5 years old with chronic constipation, a mixture of acacia fiber, psyllium fiber, and fructose, 16.8 g per day for 8 weeks, improved 77.8% of children, compared to 83% with macrogol, with no clinically significant adverse effects, but only 72% of children completed the treatment, versus 96%. Our psyllium is not recommended before age 12: in children, constipation should be managed with a pediatrician.
Elderly persons. Trials in those over 65 show no more adverse effects than in control groups, but obstruction cases often involve elderly people who drink little or have difficulty swallowing: in these situations, psyllium should be taken on medical advice.
Common misconceptions and uncertain signals
"Psyllium irritates the intestine like stimulant laxatives." Misconception. It works by retaining water in stools, whereas large wheat bran particles mechanically irritate the mucosa; a small 4-month study of 12 elderly people already described it as a non-irritating bulk-forming laxative.
"Psyllium causes constipation." True only without water. Taken improperly, with too little liquid, it can worsen constipation, note the authors of the 2018 obstruction case. Taken correctly, it is among, with pectin, the fibers whose effect on constipation is significant in the meta-analysis of 16 trials, with optimal results above 10 g per day and after at least 4 weeks.
"In powder form, there is no risk of blockage." Misconception. The 2022 case involved powder, at 5 g per day. "The more you take, the more effective it is." Dangerous misconception. The man who took approximately 47.6 g in 6 hours, even with water, developed an obstruction.
In 665 patients with a history of colorectal adenomas, 3.5 g of psyllium husk per day for 3 years was associated with more recurrences than placebo: 29.3% of patients had at least one new adenoma, compared to 20.2%, with an adjusted odds ratio of 1.67 (1.01 to 2.76). The difference was more pronounced in those whose diet was high in calcium.
Bonithon-Kopp C, Kronborg O, Giacosa A, et al. Lancet 2000;356(9238):1300-1306. DOI: 10.1016/s0140-6736(00)02813-0
Colon polyps: isolated, uncertain signal. The 2017 Cochrane review on fiber and polyp recurrence, 5 trials and 4,798 participants, found no overall difference in recurrence of at least one adenoma (relative risk of 1.04, 3,641 participants) and noted the excess recurrence with psyllium from this single trial (1.45, 376 participants). It also reports, across all fiber types, more colorectal cancers diagnosed in the fiber groups (2 trials, 2,794 participants, relative risk of 2.70, interval 1.07 to 6.85, representing approximately 1 additional percentage point of absolute risk according to the authors), without the abstract specifying which trials or which fibers, and judges the overall evidence not robust, with more than 16% loss to follow-up and weak level of evidence. If you have had polyps, discuss any fiber supplementation with your gastroenterologist.
Contaminants: no data. We found no studies in PubMed measuring heavy metals, pesticides, or other contaminants in psyllium sold as a supplement: we cannot assert anything either way.
The risk table and best practice guidelines
| Risk | Level of evidence | Who is affected |
|---|---|---|
| Gas, bloating, discomfort | Established, benign, close to placebo | Everyone, especially at the beginning and at high doses |
| Digestive obstruction | Rare, isolated cases, sometimes serious | Lack of water, overdose, difficulty swallowing, narrowing |
| Respiratory allergy | Established in occupational settings | Healthcare workers, laborers, bakers who inhale the powder |
| Anaphylaxis from ingestion | Rare, isolated cases, one fatal case published | Already sensitized individuals, atopic persons |
| Drug interactions | Possible delay for levothyroxine, only one small study; the rest poorly documented | People on medication, especially at precise dosages |
| Drop in blood sugar | Established effect, theoretical hypoglycemia | Treated diabetics |
| Mineral loss | Theoretical, weak or no measurable effect | As a precaution, space out supplements |
| Polyp recurrence | Uncertain, only one trial, not reproduced | People who have previously had polyps |
| Irritation, stimulating effect | Common misconception | No one |
| Contaminants | No studies found | Unknown |
Most of these risks are reduced by the same routine, derived from published cases and trial conditions, but which no study has tested as such.
Urgently (call 15 or 112) : chest pain or sensation that something remains stuck after taking it, inability to swallow saliva, stomach swelling and becoming painful without gas or bowel movements, repeated vomiting, widespread hives, swelling of the face, lips, or throat, breathing difficulty or fainting. Quickly : persistent pain or bloating despite a reduced dose, low blood sugar in a treated diabetic, runny nose or cough with each preparation.
100% organic blonde psyllium powder (Plantago ovata), at a rate of one tablespoon per day, or 5 to 10 g, in a large glass of water, juice, or smoothie, mixed immediately and consumed quickly before the mixture gels. To be taken at least 2 hours away from any medication.
View organic blonde psylliumOur guide to blonde psyllium and its benefits details what studies show about transit, cholesterol, and blood sugar.
Frequently asked questions
Is psyllium dangerous?
Not for most adults who take it with a large glass of water and without exceeding the dose. In trials, its adverse effects are mainly limited to gas and digestive discomfort, often just as frequent under placebo. The serious documented danger, rare, is obstruction of the esophagus or intestine, in people who drank too little, exceeded the dose, or swallowed poorly.
What are the side effects of psyllium?
Mainly gas, bloating, and abdominal discomfort, at first. In a 12-week trial involving 275 patients with irritable bowel syndrome, 71% experienced moderate flatulence under psyllium versus 78% under placebo, with no serious adverse effects. More rarely: digestive obstruction without enough water, allergy, delayed absorption of certain medications.
Does psyllium cause bloating?
It may cause some in the first few days, especially at high doses, but it is poorly fermented by the microbiota, and in a meta-analysis on constipation, fiber did not worsen bloating in the 4 trials that measured it. Starting with a small dose limits this discomfort.
What are the contraindications for psyllium?
Swallowing disorders, including those related to Parkinson's disease, narrowing of the esophagus or intestine, history of obstruction, gastric banding or digestive surgery, unexplained abdominal pain, and known allergy to psyllium. Our psyllium is not recommended before age 12. Pregnancy, breastfeeding, treated diabetes, and treatments requiring precise dosing require medical advice.
Can you take psyllium with medications?
Yes, provided you space them at least 2 hours apart. In a small study of 8 volunteers, levothyroxine taken at the same time peaked at 240 minutes instead of 180, in median, with no detectable decrease in the amount absorbed. Data are lacking for most medications: seek medical advice for lithium, anticonvulsants, or cardiac treatments.
How much water should you drink with psyllium?
A large glass per dose, at least 200 to 250 ml, mixing the powder immediately and drinking before the mixture gels, then drink normally throughout the day. In one trial, 3.5 g were dispersed in 200 ml of water. This is practical advice: no study has compared different amounts of water.
Can psyllium block the intestines?
Yes, rarely. Published cases describe obstruction in a 21-year-old man who had taken it while fasting without drinking, and in a man who had accidentally swallowed approximately 47.6 g in 6 hours; both were treated without surgery. Intestinal narrowing and intestinal paralysis are also at-risk situations.
Can you be allergic to psyllium?
Yes. In those who breathe the powder at work, sensitization is frequent (up to 26% of workers carrying IgE antibodies in one factory) and occupational rhinitis and asthma are documented. After ingestion, isolated cases of anaphylaxis are published, sometimes severe, especially in people already sensitized, most often nurses exposed to the powder at work. Rhinitis when handling the powder should prompt medical consultation before ingesting it.
Is psyllium discouraged for diabetics?
No, but it requires monitoring in diabetics under treatment. A meta-analysis of 35 trials shows a decrease of 37.0 mg/dL in fasting blood glucose and 0.97 points in HbA1c in type 2 diabetics. On insulin or sulfonylureas, discuss with your doctor and monitor your blood glucose in the first few weeks.
Can you take psyllium while pregnant?
Data are limited: the Cochrane review on constipation during pregnancy was only able to analyze 2 trials and 180 women, and judges the evidence insufficient to assess the safety of treatments. Seek the advice of your doctor or midwife.
Sources
The studies cited below were identified via PubMed.
- Bijkerk CJ, de Wit NJ, Muris JW, et al. Soluble or insoluble fibers in irritable bowel syndrome in primary care? Randomized controlled trial against placebo. BMJ, 2009;339:b3154. DOI
- Chiu AC, Sherman SI. Effects of pharmacological fiber supplements on levothyroxine absorption. Thyroid, 1998;8(8):667-671. DOI
- Gibb RD, McRorie JW, Russell DA, et al. Psyllium fibers improve glycemic control proportionally to its degradation: meta-analysis in normoglycemic subjects, those at risk for type 2 diabetes and those treated for type 2 diabetes. The American Journal of Clinical Nutrition, 2015;102(6):1604-1614. DOI
- Bardy JD, Malo JL, Séguin P, et al. Occupational asthma and IgE sensitization in a pharmaceutical company processing psyllium. The American Review of Respiratory Disease, 1987;135(5):1033-1038. DOI
- McRorie JW, McKeown NM. Understanding the physics of functional fibers in the digestive tract: an evidence-based approach to dispel misconceptions about insoluble and soluble fibers. Journal of the Academy of Nutrition and Dietetics, 2017;117(2):251-264. DOI
- McRorie JW, Chey WD. Fermented fiber supplements perform no better than placebo as a laxative. Digestive Diseases and Sciences, 2016;61(11):3140-3146. DOI
- Anderson JW, Allgood LD, Lawrence A, et al. Hypocholesterolemic effects of psyllium combined with diet in hypercholesterolemic men and women: meta-analysis of 8 controlled trials. The American Journal of Clinical Nutrition, 2000;71(2):472-479. DOI
- Kang SJ, Cho YS, Lee TH, et al. Medical management of constipation in older adults: systematic review. Journal of Neurogastroenterology and Motility, 2021;27(4):495-512. DOI
- van der Schoot A, Drysdale C, Whelan K, Dimidi E. Effect of fiber supplementation on chronic constipation in adults: updated systematic review and meta-analysis of randomized controlled trials. The American Journal of Clinical Nutrition, 2022;116(4):953-969. DOI
- Stack PE, Thomas E. Pharmacobezoar: an evolving new entity. Digestive Diseases, 1995;13(6):356-364. DOI
- Shin S, Kim JH, Mun YH, Chung HS. Acute esophageal obstruction following ingestion of psyllium husk powder: a case report. World Journal of Clinical Cases, 2022;10(7):2336-2340. DOI
- Hefny AF, Ayad AZ, Matev N, Bashir MO. Intestinal obstruction caused by a laxative (psyllium): a case report and literature review. International Journal of Surgery Case Reports, 2018;52:59-62. DOI
- Penny P, Lorch S. Psyllium overdose during colonoscopy preparation resulting in intestinal pneumatosis. ACG Case Reports Journal, 2025;12(9):e01820. DOI
- Fernandez-Martinez MN, Hernandez-Echevarria L, Sierra-Vega M, et al. Randomized clinical trial evaluating the effects of Plantago ovata husk in Parkinsonian patients: modifications of levodopa pharmacokinetics and biochemical parameters. BMC Complementary and Alternative Medicine, 2014;14:296. DOI
- Vanderbeek PB, Fasano C, O'Malley G, Hornstein J. Esophageal obstruction by a hygroscopic pharmacobezoar containing glucomannan. Clinical Toxicology, 2007;45(1):80-82. DOI
- Göransson K, Michaelson NG. Ispaghula powder: an occupational allergen. Scandinavian Journal of Work, Environment and Health, 1979;5(3):257-261. DOI
- Marks GB, Salome CM, Woolcock AJ. Asthma and allergy associated with occupational exposure to ispaghul and senna-based products in a pharmaceutical company. The American Review of Respiratory Disease, 1991;144(5):1065-1069. DOI
- Malo JL, Cartier A, L'Archevêque J, et al. Prevalence of occupational asthma and immunological sensitization to psyllium among long-term care hospital staff. The American Review of Respiratory Disease, 1990;142(6 Pt 1):1359-1366. DOI
- Collado-Chagoya R, Hernández-Romero J, Eliosa-Alvarado GA, et al. Anaphylaxis secondary to Plantago psyllium: a case report. Revista Alergia México, 2018;65(1):103-107. DOI
- Jungewelter S, Suomela S, Airaksinen L. Occupational IgE-mediated allergy to psyllium in contemporary gluten-free and vegan bakeries: a case of allergic rhinitis. American Journal of Industrial Medicine, 2021;64(5):431-434. DOI
- Sussman GL, Dorian W. Psyllium-induced anaphylaxis. Allergy Proceedings, 1990;11(5):241-242. DOI
- Drake CL, Moses ES, Tandberg D. Systemic anaphylaxis following ingestion of breakfast cereals containing psyllium. The American Journal of Emergency Medicine, 1991;9(5):449-451. DOI
- Vaswani SK, Hamilton RG, Valentine MD, Adkinson NF. Anaphylaxis, asthma and rhinitis induced by a psyllium-based laxative. Allergy, 1996;51(4):266-268. DOI
- Khalili B, Bardana EJ, Yunginger JW. Anaphylaxis and death associated with psyllium: a case report and literature review. Annals of Allergy, Asthma and Immunology, 2003;91(6):579-584. DOI
- Fernandez N, Lopez C, Díez R, et al. Drug interactions with dietary fiber from Plantago ovata seed husk. Expert Opinion on Drug Metabolism and Toxicology, 2012;8(11):1377-1386. DOI
- Gattuso JM, Kamm MA. Adverse effects of medications used in the management of constipation and diarrhea. Drug Safety, 1994;10(1):47-65. DOI
- Perlman BB. Interaction between lithium salts and psyllium husk. Lancet, 1990;335(8686):416. DOI
- Ziai SA, Larijani B, Akhoondzadeh S, et al. Psyllium significantly reduced blood glucose and glycated hemoglobin in ambulatory diabetic patients. Journal of Ethnopharmacology, 2005;102(2):202-207. DOI
- Heaney RP, Weaver CM. Effect of psyllium on calcium absorption from meals consumed simultaneously. Journal of the American Geriatrics Society, 1995;43(3):261-263. DOI
- Burton R, Manninen V. Influence of a psyllium-based fiber preparation on fecal and blood parameters. Acta Medica Scandinavica. Supplementum, 1982;668:91-94. DOI
- Rungsiprakarn P, Laopaiboon M, Sangkomkamhang US, et al. Interventions for treating constipation during pregnancy. Cochrane Database of Systematic Reviews, 2015;2015(9):CD011448. DOI
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- Bonithon-Kopp C, Kronborg O, Giacosa A, et al. Calcium and fiber supplementation to prevent recurrence of colorectal adenomas: a randomized intervention trial. Lancet, 2000;356(9238):1300-1306. DOI
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