Psyllium husk

Also known as psyllium, metamucil, ispaghula, psylium.

Last reviewed October 9, 2026 · Jump to references

What is Psyllium husk?

In plain words

Psyllium husk is fibre from the outer coating of a plant seed. The body does not fully digest it; instead, it absorbs water and forms a gel that helps make stools softer and easier to pass. Researchers study it for constipation, cholesterol levels and blood sugar control, with good evidence for constipation relief and modest cholesterol lowering. It can cause gas or bloating and may cause choking or blockage if swallowed without enough liquid.

Technical definition

Psyllium husk is a gel-forming dietary fibre derived from the outer seed coat of Plantago ovata, composed largely of poorly digested arabinoxylan polysaccharides. It acts physically rather than through a specific receptor: water retention increases stool bulk and softness, while intestinal viscosity influences nutrient absorption and bile acid reabsorption. In the United States, psyllium is marketed in dietary supplements and regulated as an active ingredient in over-the-counter bulk-forming laxatives.

Educational information only. This page does not provide medical advice or determine whether a supplement is appropriate for you. Review supplements with a qualified healthcare professional, especially if you take medication, are pregnant, have surgery scheduled, or have a chronic medical condition.

Evidence by use

Each use is rated on its own. There is no single overall effectiveness score.