Harrison Hairball is a 4 year old long hair siamese. He is very large, but healthy. From time to time (at least once a week), Harrison eats until he vomits. I have had him since he was about 6 weeks old and there has never been a food shortage. I have tried all kinds of different foods for him such as Eagle Pak, Iam's, Eukanuba, Sensible Choice, (No grocery store junk), and it doesn't seem to make a difference. Does anyone have any suggestions for poor Harrison?