Psyllium husk is a fiber supplement that promotes intestinal movement by increasing the bulk of one's stool, according to WebMD. The additional bulk aids in the relief of constipation.
Psyllium husk increases the amount of water in the stool, which makes stool softer and easier to pass, according to WebMD. It is also sometimes used to treat symptoms of irritable bowel syndrome.
This supplement is taken orally, usually as a powder mixed with liquid or in wafer form, but always with a full glass of water. Psyllium husk sometimes also decreases the absorption of medications, making it important to take the supplement at least two hours after taking other drugs.