The husk of Psyllium seed is the actual coating of mucilage around the seed. It is considered pure dietary fiber and are the only part of the plant used in manufacturing Psyllium products. The husk is composed mostly of a fiber called hemicellulose which is a complex carbohydrate found in whole grains, fruits and vegetables. Hemicellulose is indigestible, however, it is partially broken down in the colon and feeds the friendly intestinal flora.