What happens if a pet dog goes hungry for two days?

An adult pet dog usually survives two days without food if given enough water, or it easily dehydrates. A small dog or a puppy under 5 months stores little energy, so two days of hunger may cause dehydration and electrolyte imbalance, even acidosis and death in severe cases.

Therefore avoid letting the dog go hungry; in special cases prepare a food-dispensing toy, or ask a friend to feed it when you travel.