When you are suffering from longstanding or chronic diarrhea, such as irritable bowel syndrome, or IBS, fiber supplements can play a key role in halting the diarrhea. According to gastroenterologist Dr. Paul McNeely, "fiber can't work miracles, but if you have loose stool, a lot of excess liquid in the stool, the fiber in your colon will absorb and firm up the stool--which helps the diarrhea." Since you likely don't get enough soluble fiber in your daily diet, you should add a fiber supplement when suffering from a bout of diarrhea.
The active ingredient in Citrucel is methylcellulose, which is a bulk-forming agent. Therefore, it acts to give bulk form to your diarrhea. It comes in capsule or powder form and is usually prescribed once or twice daily. Possible side effects include nausea, vomiting or abdominal cramps, but it is generally well tolerated.
Inulin, which is the active fiber ingredient in FiberChoice, exists naturally in foods like bananas, asparagus and rye. You should normally take two tablets per day during a diarrhea phase; this equates to 4 mg of fiber. With FiberChoice, gas and bloating is a reported side effect, as is nausea.
Polycarbophil, the active ingredient within Fibercon, is also a bulk-forming agent. It can be used to treat acute and chronic diarrhea. It is available as a pill, or as chewable tablets. It can be taken from one to four times a day, depending on your doctor's recommendation. Side effects include bloating, gas, vomiting and upset stomach.
Metamucil contains psyllium, another bulking agent. Psyllium absorbs liquid through the intestines, thus enabling watery stool to form bulk. Metamucil can be purchased as powdered drinks, capsules, granules or wafers. Typical side effects may include itching, stomach pain, nausea or vomiting.
Unlike the previous four agents, Unifiber contains an insoluble fiber--cellulose. It comes as a tasteless, fine powder that can be mixed with drinks such as water or juice. This also acts as a bulking agent. Unifiber is generally well tolerated, and nausea is the only frequently reported side effect.