Hello - Perdiem is the same as Metamucil, it's made from psyllium. It's a great form of soluble fiber for many IBS symptoms, though Citrucel (which is made from methylcellulose) is less likely to cause bloating and gas in some people.The great thing about soluble fiber (both the supplements and the foods, such as rice, oatmeal, pasta, potatoes) is that it normalizes bowel function from either extreme. Nothing else will do this. Soluble fiber soothes the GI tract and regulates the contractions of its muscles, which means that it slows the peristaltic waves in people who have diarrhea but increases the rate for people with constipation. It also normalizes the water content of fecal matter, so it helps both diarrhea and constipation this way as well.Unfortunately, soluble fiber supplements are marketed as laxatives, but they're not. They will certainly help constipation, but they will work just as well for diarrhea. And, if someone with totally normal bowel function takes them, they won't do a darn thing (except good things like keep their bowel function normal, and lower their LDL "bad" cholesterol levels, stabilize their blood sugar, and make their hearts healthier). It does frustrate me that soluble fiber supplements are marketed as laxatives, because people with IBS-D are (understandably) afraid to try them as a result. It's equally frustrating that soluble fiber foods are mistakenly believed to help diarrhea but not constipation. All soluble fiber works the same way - it just normalizes those gut contractions and bowel function. So eating things like rice, oatmeal, pasta, etc. will have the same effect as taking Metamucil or Citrucel. If you're constipated, they'll help. If you have diarrhea, they'll help. If you alternate between d and c, they'll still help. And once you're stabilized, soluble fiber will help keep you that way on a daily basis.Hope this helps a bit, and that you're feeling better soon.Best, Heather
