Last reviewed: August 2026
A small amount of milk is unlikely to cause serious harm, but many adult dogs are lactose intolerant to some degree, and larger amounts commonly cause diarrhoea and stomach upset.
Dogs largely lose the ability to digest lactose efficiently after puppyhood, similar to many adult humans. This isn't toxicity in the traditional sense — it's a digestive intolerance that causes GI upset rather than a dangerous reaction, and severity varies a lot between individual dogs.
General veterinary toxicology consensus, cross-referenced against the Merck Veterinary Manual and ASPCA Animal Poison Control Center food hazard references. See How We Source This for our methodology.
This page is general educational information, not a substitute for veterinary advice.