MSM probably won't help it much in any way. Look into the intestinal health and cleansing forums. Sounds like whoever you're speaking for needs to eat healthy and replenish their intestinal flora with probiotics (beneficial bacteria). Fermented drinks/foods are a good start. Kombucha, raw milk Kefir, Sauerkraut, Kim Chi, yogurt, etc... all of those should be homemade. Check out the book Wild Fermentation. There could even be some parasites
involved in the problem.