Your doctor may also advise you to take a fiber supplement like psyllium (Metamucil) or methylcellulose (Citrucel) one to three times a day. Constipation can also be avoided by drinking enough of water and other fluids throughout the day. Psyllium is a seed that grows in tropical climates. It is used as a thickening agent and dietary fiber supplement. Psyllium is able to absorb large amounts of fluid into its structure, causing it to expand substantially. This property makes it useful for treating constipation. In addition, the flour made from the seeds is very nutritious and can help provide nutrients for those who are deficient in fibers such as vitamin B12, iron, and zinc. People with chronic diverticulosis may benefit from taking fiber supplements. Fiber supplements promote healthy digestion and reduce your risk of developing complications related to diverticulosis. If you are already using a fiber supplement and it isn't helping relieve constipation, discuss with your doctor what might be causing the problem instead. There may be another reason why you aren't absorbing enough nutrients from your diet. A lack of absorption could be due to factors such as antacid use, antibiotic treatment, or having inflammatory bowel disease (IBD).