IBS does wax and wane and sometimes you have to ride out a few wax and wane cycles (which may mean trying something regularly for 6 months and tracking # of episodes and comparing with before).It is rare to find something that controlls IBS 100% of the time for all time. However, most people find things that either limit the # of bad days or limit how bad the bad things are.And, I second Linda with the every person on the planet has diarrhea from time to time. Lots of things in the diet loosen stools. Hormonal fluxes can loosen stools in some woman. Being over-tired or other physical and/or emotional stress can cause IBS symptoms in some people.I have 99% control of IIBS 96-99% of the time, but even with that once in awhile I still get some problems.It can be hard to ride out the episodes, but if people give up on everything when it stops working for a week it makes it hard to find the thing or combination of things that may reduce your symptoms 50% or 75% or 90% of the time.Internet info doesn't tend to impress doctors. Have the doctor look at the 2001 ( June I think it was) review of IBS treatments in the New England Journal of Medicine (that name they do tend to listen to more than www. lord knows how accurate the info is . com).Questran, which is similar to Colestid was listed as a recommended treatment for IBS-D.K.