Have you tried adding good fats to her diet, like coconut or flax oil? These can be stirred into oatmeal (about a tsp per day) or spread onto toast. Another idea is adding good bacteria to the intestines for better overall digestive health. Liquid, live acidophilus is great! It can be found at a health food store. There are several great tasting yogurts now. Activia is really a good one. The probiotics are really important for helping this situation get better. Does she eat too much sugar in her diet? (juices, fruits, cereals, "fruit snacks", etc) This may have caused a yeast infection in the gut, resulting in the rashy bottom. All of these things I've recommended will fight this and make it right inside so that the problem should resolve itself without forcing diarrhea.
at 1:12 AM on May. 30, 2009