it could be he's just not hungry - but TAKING HIM TO THE VETS is the only way to be sure. i wouldn't risk it, especially if he is being sick and had diharea (sp) too - this could be a symptom of Leptospirosis and is deadly. 2/3 cans? how big is the dog?

The breed type, age, level of activity, recent vaccines? Would all help to identify if there is a possible illness or other challenge here! Also...how is he acting? In general...normal? or Not playing, not interested, sleeping more, stressed. What's his stool like? Firm, runny, soft serve, hard, is he straining or does he have the runs? Lord help you, but you are expecting an awful lot from a bunch of folks who can't SEE your dog! <wink> Have you taken his temperature? Normal should be between 100.4 and 102.2...unless he just finished playing hard, then it might be a jot higher. Is he drinking a NORMAL amount of water, or a lot, or very little? It may be that he is simply BORED with this food. If he has no prior health conditions that limit WHAT you can feed him, you can try something different. Some "bored" eaters do better on a mixture of part kibble and part canned or home-cooked. What's nice about kibble is you can scatter it on the floor (unless you have greedy additional dogs!) and let him "forage" for his meals...this sometimes will stimulate a picky eater to eat. You can also put some kibble mixed with his canned and or some plain nonfat yogurt (a dab of Peanut butter, or bits of cut up Human Grade plain beef jerky (meat in other words) into a size appropriate Kong and freeze it over night or just part way through and give him THAT to work on... You can look into other brands of commercial feed or consider B.A.R.F. (GOOGLE THAT) or Homemade feed. Check out this site for more information on canine nutrition. http://www.api4animals.org/facts?p=359&more=1 If his BEHAVIOR is off, if you are unable to take his temperature...or to feel comfortable with how he seems to you..CALL YOUR VET...always in my book it is better to be SAFE THAN SORRY!