As Laurel said, in IBS people, SF soothes the colon and IF stimulates the colon. If you take in too much IF at a time, it will OVERSTIMULATE the colon. For IBS-D folks, this means diarrhea. For IBS-C folks, the overstimulation occurs and then the colon takes it one step further and shuts down - resulting in constipation.
-------------------- Formerly HanSolo. IBS, OCD, Bipolar, PTSD times 3.