Psyllium is a fiber that comes from a plant called Plantago ovata (blonde psyllium). The plant has tiny, gel-coated seeds. Psyllium is found in the seeds’ husk. Psyllium is soluble, meaning that it can dissolve in water. When preparing psyllium for commercial use, the seeds are first harvested and cleaned. In some formulations, the husks are separated from the seeds and processed; in others, the husk remains intact. Black psyllium ( P. afra), another variety of the seed, is also available.
Psyllium can be found as a dry seed or husk. It is a common ingredient in many popular laxatives and is available in powder, capsule, tablet, and wafer form.1,15
Dosages are specific to the product containing psyllium. Therefore, it is best to check the product label for the appropriate dosage. However, below is general dosage information for powdered psyllium.
Adults may take 3-6 grams of psyllium (1-2 teaspoons) in or with 8 ounces of water 2-3 times/day.1 Always take psyllium with a full glass of water (8 ounces). Also, drinking 6-8 full glasses of water each day will help prevent constipation.15
Children six years and older may take 1.5-3 grams of psyllium (1 teaspoon) in or with 4-8 ounces of water 2-3 times/day.1
Do not take psyllium for longer than one week without first consulting your doctor.26
Psyllium is primarily used to manage constipation, especially in people who do not eat enough fiber. It can be helpful for people who just had rectal surgery, are recovering from a heart attack, are on prolonged bed rest, or any other circumstance where straining during bowel movements is not advised. Patients experiencing other conditions where easy, soft bowel movements would be desirable (eg, anal fissures, hemorrhoids, pregnancy) may find psyllium helpful. Finally, psyllium can also be used to treat certain kinds of watery diarrhea.1
Psyllium works by mixing with water in the intestines to create a gel-like substance, which helps move bowels down the intestinal tract.1
A 2011 review of 3 trials with 283 subjects comparing psyllium (approximately 10 g daily) to placebo found consistently favorable results.26 In one of the studies, for example, 2 weeks of psyllium (3.6 g, 3 times daily) produced a significantly greater improvement in symptoms over placebo. Numerous other studies have also shown psyllium to be effective in relieving constipation in adults.8,10,11,12,13,23
Another small study looked at the effect of combining different laxatives to treat chronic constipation. Thirty-five men and women were randomized to either placebo or capsules containing celandine, aloe vera, and psyllium. Researchers found that those who had received the capsules had more frequent bowel movements and softer stools.13
A larger study has also shown psyllium to effectively treat chronic constipation. The multi-site, randomized, double-blind study followed 170 adults with chronic constipation. The study compared psyllium and another laxative and found in favor of psyllium for better stool softening.14 (However, this study was funded by the maker of a psyllium product.)
Some researchers have investigated psyllium’s ability to lower cholesterol, and conclusions have been mixed.2,3,6,7,16,17,18,20,24 One study found that psyllium did not have a significant cholesterol-lowering effect in subjects with normal or slightly elevated cholesterol levels. However, two separate reviews of multiple studies found in favor of psyllium’s ability to reduce both total cholesterol and LDL (“bad”) cholesterol, particularly in subjects with mild to moderate elevations on low-fat diets.2,24 An additional study found psyllium to have a modest but significant improvement for total and LDL cholesterol levels in people on low- or high-fat diets.
Another small study suggested that psyllium would be beneficial for postmenopausal women in lowering cholesterol and reducing the risk for heart diseases.3
Fiber has long been a mainstay in the treatment of constipation in patients with irritable bowel syndrome. However, it is unclear which type of fiber is more beneficial, soluble (psyllium) or insoluble (eg, bran). Two studies suggest an answer. In a systematic review of 17 studies, the authors concluded that psyllium improved certain irritable bowel syndrome symptoms more than insoluble fibers.9 This conclusion was supported by a subsequent randomized trial involving 275 adults, which found that psyllium was more effective than either bran or placebo for irritable bowel syndrome symptom relief.22
Do not use psyllium if you have difficulty swallowing, unexplained abdominal pain, nausea, or vomiting. If you have kidney disease, talk to your doctor before taking psyllium. When consuming any type of fiber, gas and bloating are possible side effects.15 Also, drink plenty of fluids when taking psyllium.
Some side effects specific to psyllium include cramps, difficulty swallowing, nausea, vomiting, skin rash, itching, and difficulty breathing.1,26,27
Some people may be sensitive to psyllium. Try to avoid inhaling psyllium particles (eg, powder), since it may cause allergic reactions, such as difficulty breathing and itchy, red eyes.27
Since the absorption of many drugs can be affected by psyllium, talk to your doctor before using psyllium if you are taking any medicine.1,15,27 Medicines of particular concern include:
Do not take psyllium at the same time you take your medicines. Psyllium should be taken at least two hours before taking your medicines or 2-4 hours afterward.15,27
2. Wei ZH, Wang H, Chen XY, et al. Time- and dose-dependent effect of psyllium on serum lipids in mild-to-moderate hypercholesterolemia: a meta-analysis of controlled clinical trials. Eur J Clin Nutr. 2009 Jul;63(7):821-827.
4. Cicero AF, Derosa G, Manca M, Bove M, Borghi C, Gaddi AV. Different effect of psyllium and guar dietary supplementation on blood pressure control in hypertensive overweight patients: a six-month, randomized clinical trial. Clin Exp Hypertens. 2007 Aug;29(6):383-394.
6. Shaffer EA, Edwards AL, Brant R, Van Rosendaal GM. Effect of time of administration on cholesterol-lowering by psyllium: a randomized cross-over study in normocholesterolemic or slightly hypercholesterolemic subjects. Nutr J. 2004 Sep 28;3:17.
7. Sprecher DL, Harris BV, Goldberg AC, et al. Efficacy of psyllium in reducing serum cholesterol levels in hypercholesterolemic patients on high- or low-fat diets. Ann Intern Med. 1993 Oct 1;119:545-554.
9. Bijkerk CJ, Muris JW, Knottnerus JA, Hoes AW, de Wit NJ. Systematic review: the role of different types of fibre in the treatment of irritable bowel syndrome. Aliment Pharmacol Ther. 2004 Feb 1;19(3):245-251.
12. Ashraf W, Park F, Lof J, Quigley EM. Effects of psyllium therapy on stool characteristics, colon transit and anorectal function in chronic idiopathic constipation. Aliment Pharmacol Ther. 1995 Dec;9(6):639-647.
15. University of Maryland Medical Center. Psyllium. University of Maryland Medical Center website. Available at: http://www.umm.edu/altmed/articles/psyllium-000321.htm. Updated May 6, 2009. Accessed September 22, 2010.
16. Uehleke B, Ortiz M, Stange R. Cholesterol reduction using psyllium husks—do gastrointestinal adverse effects limit compliance? Results of a specific observational study. Phytomedicine. 2008 Mar;15(3):153-9.
18. Shrestha S, Freake HC, McGrane MM, Volek JS, Fernandez ML. A combination of psyllium and plant sterols alters lipoprotein metabolism in hypercholesterolemic subjects by modifying the intravascular processing of lipoproteins and increasing LDL uptake. J Nutr. 2007 May;137(5):1165-70.
24. Anderson JW, Allgood LD, Lawrence A, et al. Cholesterol-lowering effects of psyllium intake adjunctive to diet therapy in men and women with hypercholesterolemia: meta-analysis of 8 controlled trials. Am J Clin Nutr. 2000 Feb;71(2):472-9.
26. Suares NC, Ford AC. Systematic review: the effects of fibre in the management of chronic idiopathic constipation. Aliment Pharmacol Ther. 2011;33(8):895-901.
27. Psyllium. DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T908953/Psyllium. Updated October 6, 2017. Accessed October 12, 2017.
Last reviewed December 2015 by EBSCO CAM Review Board Last Updated: 10/12/2017