is metamucil given for constipation
1 Review. Metamucil is a bulk-forming fiber that is used to treat constipation and may also reduce cholesterol when taken every day. The generic name for this fiber is psyllium. The fiber absorbs liquid in the intestines and swells and forms a bulky stool, which is easy to pass. The active ingredients are the seed husks of the psyllium plant. The Metamucil brand has been in existence since 1934.