This was in regards to when they have diarrhea. In my year in the shelter system, when cats have diarrhea and we remove wet food generally the diarrhea stops.I think I have to disagree with cifelliac regarding the dry food.. unless it is novel protein.. Dry food is notorious for having many added junk to it..
Wet food is much better for cats.
Overall, yes, wet food is WAY better then dry food, but not when they are having loose stools. Once the problem is diagnosed I would recommend they introduce wet food again to the diet.