My cat was diagnosed with IBS 3 years ago. For 2 of those years, I fed her a prescription cat food recommended by my Vet, IVD Duck and Pea dry. She still threw up about once a week. Then a member in an IBS group suggested EVO for her because it was grain free and had a high protein content. My cat has done great, she has not been sick for over 1 month now since I switched her to the new food, and I am convinced it is because of the EVO. Plus, the EVO is actually less expensive that the prescription food!