My two cats eat three wet meals a day (one at 6 a.m. one around 4 p.m and then at bedtime around 10 p.m.) and one dry meal. The canned food is all grain free, various brands, various proteins. They get one 3 oz can split between the two cats at the morning and afternoon feeding and about 1/2 a 3 oz can split at the bedtime meal. It doesn't matter what the brand or flavor...3 oz (1 1/2 oz per cat) is the maximum they'll eat at any meal. The dry meal is 1/3 cup split between the two cats around 7 or 8 at night. I've been using Wellness Core Turkey and Duck (fish and chicken free) and they both did really well on that. I'd read so much about Orijin that I thought I might want to use that as a "back up" dry so I started mixing in a very, small amount of Orijin Regional Red with the Wellness (small meaning a 12 oz sample pack mixed in with about 2 1/2 pounds of the Wellness Core). Immediately after eating this meal with the Orijin mixed in, one of my cats, BamBam, vomited everything back up....and then vomited a couple of more times over the next hour. The other cat, Sammy, was fine with it. This has happened twice ---they've had the mixture for almost a week, so two out of 5 or 6 times. I did notice last night when it happened, that the 1/3 cup seemed to have a little more of the darker Orijin than usual (not mixed as well I guess). Does anyone think the Orijin Red could be too rich for him...or maybe one of the weird novel proteins like Wild Boar or Bison is a problem? He does eat the dry food pretty fast so I think it could also be that, except he never did it before I mixed in the Orijin. He's wanted his bedtime meal both times and held that down fine....just vomits after the dry meal. He was having some hairball problems and vomiting hairballs a couple of times a week, but I started him on the Vet's Best and have been using the Furminator and he's not throwing up hairballs anymore.