What happens if a cat eats dog food occasionally?

It is fine for a cat to eat a little dog food occasionally, because most nutrients in cat and dog food are basically the same, and dog food can substitute when cat food runs short. But avoid long-term feeding, since dog food is lower in protein and chronic feeding causes nutritional deficiency and poor development.

Also, dog food is higher in starch, and after eating it a cat may suffer indigestion with soft stool, diarrhea or vomiting.