Psyllium husk

A gel-forming fiber, taken as a supplement for constipation. Always take it with plenty of water.

Updated November 10, 2026

What it is

Psyllium husk is the seed coat of Plantago ovata, also called blond psyllium. It’s mostly soluble fiber and forms a gel with water.

What it does

Constipation: it absorbs liquid in your gut, swells and forms a bulky stool that’s easy to pass.
Heart health: in an FDA-authorized claim, 7 g a day of soluble fiber from psyllium husk, in a diet low in saturated fat and cholesterol, may reduce the risk of heart disease.

How to take it

Take each dose with at least 8 oz (a full glass) of water or another drink.
Follow the dose on the label.
Keep digoxin, aspirin and nitrofurantoin at least 3 hours apart from psyllium, and ask a pharmacist about your other medicines.

Don’t take psyllium if you have trouble swallowing. If you get chest pain, vomiting, or trouble swallowing or breathing after a dose, get medical help right away.

Questions

Is psyllium husk soluble or insoluble fiber?

Mostly soluble. A tablespoon (5 g) has about 3.5 g of fiber, most of it soluble.

Is psyllium a laxative?

Yes, a bulk-forming one. It absorbs liquid in your gut, swells and forms a bulky stool that’s easy to pass.

How much water should you take with psyllium?

At least 8 oz (a full glass) with every dose. Without enough liquid it can swell and block your throat or esophagus.

Can you take psyllium with other medicines?

Check with your pharmacist. MedlinePlus says not to take digoxin, aspirin and other salicylates, or nitrofurantoin within 3 hours of psyllium.

How much psyllium is good for your heart?

The FDA’s heart health claim uses 7 g a day of soluble fiber from psyllium husk, as part of a diet low in saturated fat and cholesterol. Follow the dose on the label.

Sources

General information, not medical advice. If you have a health condition or take medicines, ask your doctor before adding a fiber supplement.