Why does my dog drool when I'm eating

Salivation in response to the sight and smell of food is triggered by the nervous system automatically, well before any conscious decision by the dog, which means drooling itself is not something a dog can simply choose to stop, unlike staring or whining.

Breeds with loose jowls, such as Bloodhounds, Saint Bernards, and Mastiffs, physically retain less saliva in the mouth and drool more visibly than a tighter lipped breed would in the exact same situation, independent of how excited either dog actually is about the food.

Sudden, unusual drooling that happens away from any food related trigger, especially alongside lethargy, pawing at the mouth, or reluctance to eat, is a different situation and worth a vet check rather than being assumed to be simple food anticipation.

The same conditioned salivary reflex that Ivan Pavlov famously documented in dogs over a century ago is at work here, where the mere anticipation of food, its smell, the sound of preparation, or simply watching someone eat, triggers saliva production well before any food is actually available. This is a universal feature of canine physiology rather than a quirk specific to any individual dog, and there is no training or behavioral fix needed for ordinary food anticipation drooling, since it causes the dog no discomfort and simply reflects a normally functioning digestive system gearing up in advance.