In reading through a recent report on the autoimmune disease treatment options (mostly from a market sizing perspective), I came across a therapy called fecal bacteriotherapy. The treatment is a last resort option for patients with pseudomembranous colitis or ulcerative colitis. The therapy is based on the premise that these diseases are caused by imbalances of bacteria in the colon or small intestine and so by transplanting fecal bacteria from a healthy individual (i.e. microflora from someone that doesn't have any GI issues) to an afflicted patient you restore the balance of bacteria in the gut. By introducing a "healthy" mix of bacteria, you can replace whatever pathogenic bacteria is there (e.g. Clostridium difficile in the case of pseudomembranous colitis) with healthy, probiotic bacteria. It's not unlike other probiotic therapies, but this one literally uses all the bacteria from a healthy person rather than just a subset.I found this interesting for two reasons. One is that it's interesting to see a related disorder where they have pinpointed the bacterial agent that causes the disease. And second, it might be another last resort option for people for Crohn's or UC.