There are scores of clinical trials and excellent reviews evaluating the role of probiotics in colitis ( Ewaschuk, 2006) and a growing body of data looking specifically for their role in ameliorating the GI side effects of radiation. In one study, VSL#3, a high-potency probiotic preparation, reduced the incidence and severity of radiation-induced diarrhea. The dosage used was 3 packets per day. ( Delia, 2007) Another study showed that patients receiving pelvic radiotherapy had better stool consistency while using a Lactobacillus casei probiotic drink ( Giralt, 2008). Prebiotics are fermented to short chain fatty acids, which are necessary for colonic enterocyte metabolism and stimulate the growth of “friendly” bacteria, making the use of fructo-oligosaccharides, inulin and barley also beneficial.