What is it?
Black psyllium adds bulk to the stool which might help with constipation, diarrhea, and irritable bowel syndrome (IBS). It also controls how quickly sugars are absorbed from the gut, which might help control blood sugar levels in people with diabetes.
People commonly use black psyllium for treating and preventing constipation. It is also used for diarrhea, obesity, diabetes, high blood pressure, and many other conditions, but there is no good scientific evidence to support most of these uses.
Don't confuse black psyllium with blond psyllium. These are not the same.
How effective is it?
Natural Medicines Comprehensive Database rates effectiveness based on scientific evidence according to the following scale: Effective, Likely Effective, Possibly Effective, Possibly Ineffective, Likely Ineffective, Ineffective, and Insufficient Evidence to Rate.
The effectiveness ratings for BLACK PSYLLIUM are as follows:
- Constipation. Consuming soluble dietary fiber by mouth, including black psyllium, is effective for short-term constipation. It's found in over-the-counter (OTC) products for this use.
Likely effective for...
- Heart disease. Consuming foods high in soluble fiber, including black psyllium, as part of a low-fat, low-cholesterol diet, might help prevent heart disease. At least 7 grams of psyllium husk must be consumed daily.
Is it safe?
Black psyllium is likely unsafe when consumed without enough water. It might cause choking or block the gastrointestinal (GI) tract.
Special precautions & warnings:Pregnancy and breast-feeding: Taking black psyllium during pregnancy or breast-feeding seems to be safe, as long as enough fluids are taken with each dose.
Gastrointestinal (GI) disorders: Don't use black psyllium if you tend to develop hard stools in the rectum due to GI tract narrowing, or have a condition that can lead to obstruction, such as spastic bowel.
Phenylketonuria: Some black psyllium products might be sweetened with aspartame (NutraSweet). If you have phenylketonuria, avoid these products.
Swallowing disorders: Do not use black psyllium if you have problems swallowing. Black psyllium might increase your risk of choking.
Are there interactions with medications?
- Carbamazepine (Tegretol)
- Black psyllium contains large amounts of fiber. Fiber can decrease how much carbamazepine the body absorbs. This might decrease the effects of carbamazepine.
- Black psyllium contains large amounts of fiber. Fiber can decrease how much lithium the body absorbs. This might decrease the effects of lithium. To avoid this interaction, take black psyllium at least 1 hour after lithium.
- Metformin (Glucophage)
- Black psyllium contains large amounts of fiber. The fiber in psyllium might increase how much metformin the body absorbs. This might increase the effects of metformin. To avoid this interaction, take black psyllium 30-60 minutes after medications you take by mouth.
- Olanzapine (Zyprexa)
- Black psyllium contains large amounts of fiber. Fiber can decrease how much olanzapine the body absorbs. This might decrease the effects of olanzapine.
- Digoxin (Lanoxin)
- Black psyllium is high in fiber. Fiber can decrease how much digoxin the body absorbs. This might decrease the effects of digoxin.
- Ethinyl estradiol
- Ethinyl estradiol is a form of estrogen. Psyllium can decrease how much ethinyl estradiol the body absorbs. But it is unlikely that this will reduce the effects of ethinyl estradiol.
- Medications taken by mouth (Oral drugs)
- Black psyllium contains large amounts of fiber. Fiber can decrease, increase, or have no effect on how much medicine the body absorbs. Taking black psyllium along with medicine you take by mouth can impact the effects of your medicine. To prevent this interaction, take black psyllium 30-60 minutes after medications you take by mouth.
Are there interactions with herbs and supplements?
- Taking black psyllium with iron supplements can reduce the amount of iron that the body absorbs. To avoid this interaction, take iron supplements one hour before or four hours after black psyllium.
- Psyllium seems to slightly reduce the amount of riboflavin that the body absorbs. But this probably isn't a big concern.
Are there interactions with foods?
- Taking psyllium can make it difficult to digest fat from the diet. This can increase the amount of fat lost in the stool. Taking psyllium with meals over a long period of time might also affect nutrient absorption. In some cases, it might be necessary to take vitamin or mineral supplements.
How is it typically used?
To learn more about how this article was written, please see the Natural Medicines Comprehensive Database methodology.
- Merrick C, Madden CA, Capurso NA. A Case of Blunted Orally Disintegrating Olanzapine Effect Due to Coadministered Psyllium. J Clin Psychiatry 2021;82:20cr13633. View abstract.
- Chiu AC, Sherman SI. Effects of pharmacological fiber supplements on levothyroxine absorption. Thyroid. 1998;8:667-71. View abstract.
- Rivers CR, Kantor MA. Psyllium husk intake and risk of type 2 diabetes: an evidence-based scientific and regulatory review of a qualified health claim conducted by the US Food and Drug Administration. Nutr Rev 2020 Jan 22:nuz103. doi: 10.1093/nutrit/nuz103. Online ahead of print. View abstract.
- Clark CCT, Salek M, Aghabagheri E, Jafarnejad S. The effect of psyllium supplementation on blood pressure: a systematic review and meta-analysis of randomized controlled trials. Korean J Intern Med 2020 Feb 19. doi: 10.3904/kjim.2019.049. Online ahead of print. View abstract.
- Darooghegi Mofrad M, Mozaffari H, Mousavi SM, Sheikhi A, Milajerdi A. The effects of psyllium supplementation on body weight, body mass index and waist circumference in adults: A systematic review and dose-response meta-analysis of randomized controlled trials. Crit Rev Food Sci Nutr 2020;60:859-72. doi: 10.1080/10408398.2018.1553140. View abstract.
- Diez R, Garcia JJ, Diez MJ, Sierra M, Sahagun AM, Fernandez N. Influence of Plantago ovata husk (dietary fiber) on the bioavailability and other pharmacokinetic parameters of metformin in diabetic rabbits. BMC Complement Altern Med. 2017 Jun 7;17:298. View abstract.
- Department of Health and Human Services, Food and Drug Administration. Laxative drug products for over-the-counter human use: psyllium ingredients in granular dosage forms. Final Rule. Federal Register; March 29, 2007: 72.
- Code of Federal Regulations, Title 21 (21CFR 201.319). Specific labeling requirements - water-soluble gums, hydrophilic gums, and hydrophilic mucilloids. Available at www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr=201.319. Accessed December 3, 2016.
- Code of Federal Regulations, Title 21 (21CFR 101.17). Food labeling warning, notice, and safe handling statements. Available at www.ecfr.gov/cgi-bin/text-idx?SID=20f647d3b74161501f46564b915b4048&mc=true&node=se21.2.101_117&rgn=div8. Accessed December 3, 2016.
- Code of Federal Regulations, Title 21 (21CFR 101.81). Chapter IB, part 101E, section 101.81 "Health claims: soluble fiber from certain foods and risk of coronary heart disease (CHD)." Available at www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/cfrsearch.cfm?fr=101.81. Accessed December 3, 2016.
- Akbarian SA, Asgary S, Feizi A, Iraj B, Askari G. Comparative study on the effect of Plantago psyllium and Ocimum basilicum seeds on anthropometric measures in nonalcoholic fatty liver patients. Int J Prev Med 2016;7:114. View abstract.
- Semen plantaginis in: WHO Monographs on Selected Medicinal Plants, volume 1. World Health Organization, Geneva, 1999. Available at http://apps.who.int/medicinedocs/en/d/Js2200e/. Accessed November 26, 1026.
- Fernandez N, Lopez C, Díez R, et al. Drug interactions with the dietary fiber Plantago ovata husk. Expert Opin Drug Metab Toxicol 2012;8:1377-86. View abstract.
- Frati-Munari, A. C., Fernandez-Harp, J. A., Becerril, M., Chavez-Negrete, A., and Banales-Ham, M. Decrease in serum lipids, glycemia and body weight by Plantago psyllium in obese and diabetic patients. Arch Invest Med (Mex) 1983;14:259-268. View abstract.
- Ganji V, Kies CV. Psyllium husk fibre supplementation to soybean and coconut oil diets of humans: effect on fat digestibility and faecal fatty acid excretion. Eur J Clin Nutr 1994;48:595-7. View abstract.
- Garcia JJ, Fernandez N, Diez MJ, et al. Influence of two dietary fibers in the oral bioavailability and other pharmacokinetic parameters of ethinyloestradiol. Contraception 2000;62:253-7. View abstract.
- Robinson DS, Benjamin DM, McCormack JJ. Interaction of warfarin and nonsystemic gastrointestinal drugs. Clin Pharmacol Ther 1971;12:491-5. View abstract.
- Nordstrom M, Melander A, Robertsson E, Steen B. Influence of wheat bran and of a bulk-forming ispaghula cathartic on the bioavailability of digoxin in geriatric in-patients. Drug Nutr Interact 1987;5:67-9.. View abstract.
- Roe DA, Kalkwarf H, Stevens J. Effect of fiber supplements on the apparent absorption of pharmacological doses of riboflavin. J Am Diet Assoc 1988;88:211-3.. View abstract.
- Frati Munari AC, Benitez Pinto W, Raul Ariza Andraca C, Casarrubias M. Lowering glycemic index of food by acarbose and Plantago psyllium mucilage. Arch Med Res 1998;29:137-41. View abstract.
- Rossander L. Effect of dietary fiber on iron absorption in man. Scand J Gastroenterol Suppl 1987;129:68-72.. View abstract.
- Kaplan MJ. Anaphylactic reaction to "Heartwise." N Engl J Med 1990;323:1072-3. View abstract.
- Lantner RR, Espiritu BR, Zumerchik P, Tobin MC. Anaphylaxis following ingestion of a psyllium-containing cereal. JAMA 1990;264:2534-6. View abstract.
- Schwesinger WH, Kurtin WE, Page CP, et al. Soluble dietary fiber protects against cholesterol gallstone formation. Am J Surg 1999;177:307-10. View abstract.
- Fernandez R, Phillips SF. Components of fiber bind iron in vitro. Am J Clin Nutr 1982;35:100-6. View abstract.
- Fernandez R, Phillips SF. Components of fiber impair iron absorption in the dog. Am J Clin Nutr 1982;35:107-12. View abstract.
- Vaswani SK, Hamilton RG, Valentine MD, Adkinson NF. Psyllium laxative-induced anaphylaxis, asthma, and rhinitis. Allergy 1996;51:266-8. View abstract.
- Agha FP, Nostrant TT, Fiddian-Green RG. Giant colonic bezoar: a medication bezoar due to psyllium seed husks. Am J Gastroenterol 1984;79:319-21. View abstract.
- Perlman BB. Interaction between lithium salts and ispaghula husk. Lancet 1990;335:416. View abstract.
- Etman M. Effect of a bulk forming laxative on the bioavailablility of carbamazepine in man. Drug Dev Ind Pharm 1995;21:1901-6.
- Cook IJ, Irvine EJ, Campbell D, et al. Effect of dietary fiber on rectosigmoid motility in patients with irritable bowel syndrome: A controlled, crossover study. Gastroenterology 1990;98:66-72. View abstract.
- Covington TR, et al. Handbook of Nonprescription Drugs. 11th ed. Washington, DC: American Pharmaceutical Association, 1996.
- Gruenwald J, Brendler T, Jaenicke C. PDR for Herbal Medicines. 1st ed. Montvale, NJ: Medical Economics Company, Inc., 1998.
- McGuffin M, Hobbs C, Upton R, Goldberg A, eds. American Herbal Products Association's Botanical Safety Handbook. Boca Raton, FL: CRC Press, LLC 1997.
- Leung AY, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics. 2nd ed. New York, NY: John Wiley & Sons, 1996.
- Wichtl MW. Herbal Drugs and Phytopharmaceuticals. Ed. N.M. Bisset. Stuttgart: Medpharm GmbH Scientific Publishers, 1994.
- The Review of Natural Products by Facts and Comparisons. St. Louis, MO: Wolters Kluwer Co., 1999.
- Newall CA, Anderson LA, Philpson JD. Herbal Medicine: A Guide for Healthcare Professionals. London, UK: The Pharmaceutical Press, 1996.
- Blumenthal M, ed. The Complete German Commission E Monographs: Therapeutic Guide to Herbal Medicines. Trans. S. Klein. Boston, MA: American Botanical Council, 1998.
- Monographs on the medicinal uses of plant drugs. Exeter, UK: European Scientific Co-op Phytother, 1997.