How much pesto is safe for a dog to lick, and when does the garlic in it become dangerous?

There is no truly safe amount of pesto for dogs because it contains garlic, which is toxic. Even a small lick could irritate a sensitive stomach due to the garlic, cheese, and oils. The danger increases with the amount consumed, as garlic can damage red blood cells and cause anemia, but this typically requires eating a larger quantity over time. It's best to avoid giving pesto entirely. If your dog licked a tiny bit off a spoon, watch for vomiting or diarrhea and call your vet if you see those signs.