Suggest Treatment For Persistent Diarrhea And Gas In An Infant

my daughter has had diarrhea all her 26 months of life. she wakes up in the night and passes gas a lot and and has sulfur burps. she does not metabolize carbohydrates so we eliminated all gluten from her diet and that has helped some. she drinks kefir to try to balance her stomach bacteria. our pediatrician has not been helpful and neither has the gi doctor. i know there is something wrong but just dont know what to do.