Because of the problems that my Amanda had with her teeth and gums years ago, primarily because of her only eating canned food, I, as you all probably know, alway preach the use of dry food as much as possible. Well, I have one more reason for dry food to pass along to you. I don't remember if this had been mentioned before or not. Yesterday, Amanda had diarrhea which was extremely dark, almost black, which to me indicated blood or liver problem. So I took her to the vet immediately. Well, poor girl, in addition to everything else, has a duodenal ulcer. My vet thinks part of the reason for the ulcer may be that since she is totally on canned food -- at 16 and no teeth -- she is not getting any real fiber, which helps push things through her system quickly. To help alleviate this, I am now giving her brewers yeast flakes with her canned food, plus the medication for the ulcer. So, dry food is best for your dog for more than one reason. However, if there is some reason you dog must be on canned food, maybe check with your vet on using some natural type of fiber to supplement the canned food.