A dog that vomits undigested dog food in the middle of the night may be eating too much or eating too fast, causing gastrointestinal discomfort. It may also be that the dog's food is suddenly changed, which irritates the gastrointestinal tract and causes vomiting. When a dog vomits dog food, it is necessary to fast for half a day and then feed some probiotics. When feeding, it should be fed in small amounts and multiple times, and not too much at one time.