Hanna,This has come up here before, and as you can see, its variable among diff people. I don't get colds or the flu myself, but I haven't since I was a kid.When they talk of increased immune cell activation along the intestinal wall(home to abt 70% of the body's total immune sys cells), its referring to inc'd mast & EC cells.It leads to the low-grade submucosl inflammation found in IBS...There are diff theories, conflicting studies as to how this comes about. Some believe it has to do with seratonin and a malfunctining brain-gut-immune axis...others, like myself, believe it has to do with bacterial dysbiosis...Low innate beneficial bacteria(which all in one way or another help keep inflammatino in check.)There's also another theory which I truly hope is very wrong, but probably does apply to some IBSrs. Its that the initial inflammation is triggered by an infection, this triggers inflamation, and for some reason, us blamed on genetics, the inflammation continues even though the initial infection has been cleared up...That's just too final for me. And in my case, I've gotten back to 98% normal taking the psyllium, GSE, & probiotics--so it can't be imm sys cells which can't down-regulate due to a genetic flaw, right?The answers will come some day...Fingers are crossed!That's my take on the whole thing anyways. Talissaps, there was a USA Today article that said "happy people get fewer colds..."________________________________________