Hi, Claire -My dr. recommended fiber and i'm currently taking it (or rather, trying to take it regularly). For me, i was recommended "benefiber" and was told by doc that it'd make me worse at first for about 2-3 weeks before my body start adjunsting to it. It's been a month since the first day i took it -- it's true that at first my D got worse and with much more pain than before. and this lasted about 2-3 weeks. Now the D got better (not all the time, but on and off), but the pain's still pretty much the same.I also heard that it also depends on what kind of fiber you use -- many people think benefiber works the best, but some prefer citrical (sp??). A lot of people don't like metanusil 'cause it makes their symptoms a LOT worse. Individuals are different, too! So far I've tried only benefiber and strangely didn't experience the "miracle" effect that many people do after taking it for just one week... What kind have you tried?P.S., I must have been writing when Kathleen posted. I see now that for some people fiber just won't work...