How long can a dog go without eating?

A healthy adult dog skipping one meal is usually not a worry if otherwise normal. Call a vet if an adult dog hasn't eaten for 24–48 hours.

Call sooner if: it's a puppy, a senior or a small breed, or there's also vomiting, diarrhea, tiredness, pain or drinking less. Not eating is often a sign of nausea, dental pain or illness rather than pickiness.