The Royal Canin Gastro RX food is excellent for pups who need it! It was recommended for my Cookie who has IBD and Lymphangectasia. I opted to do a consult with a vet nutritionist and home cook for her, but I wouldn't hesitate to use ANY of the RX foods as I have used many of them over the years. In a really sick pup, these foods can save lives!
This website is run by a vet nutrionist and is very informative:
www.petdiets.com