Archie's been on Canidae ALS since I got him one year ago. Three times I've tried to switch his food; unsuccessfully. First to Blue Buffalo, Then to Evo, and Now to Before Grain (Chicken). Blue buffalo he got fairly ill with. Evo and B.G. he transitions fine, over about a 1-2 week period-- Normal poop and no vomiting. Now that he's been on B.G. for about 2 weeks, he begins vomiting- mostly in the morning. It's bits of things he ate the prior day, not just bile. And I fed him right before bed last night- so it's not acid reflux. He's got a vet appt. today anyway, but I was wondering what this might be an intolerance to- or what the problem is. Maybe it's the fact that it's grain free? Dunno. I just know the vet will simply tell me "That stuff is bad, switch to Science Diet Sensitive Stomach!" Either way, he did perfectly fine on Canidae. I just thought I would try to switch it up a little, especially now after their formula changes. I could always leave well enough alone and switch him back... Just to add: Archie is about 10 years old, he's 40 lbs.