Big, wet sloppy dog kisses are one of the best things about owning a dog — at least, according to some people. For others, their reaction to dog licking is more of a shriek of disgust. Whether you enjoy playing kissy-face with your dog or not, it’s best to understand if you should be allowing these dog kisses or not.

Why Dogs Lick

Licking is a behavior that dogs learn from birth, says Animal Planet^[1]. As soon as puppies are born, their mother licks them in order to clean them and stimulate breathing, and the pups learn to lick their mother in return. This licking instinct never goes away. The process of licking releases endorphins that provide a sense of pleasure and help to relieve stress, which is why some dogs resort to obsessive licking behaviors when they get anxious. In dog packs, licking also serves as a sign of submission to more dominant members of the pack. When it comes to dogs licking humans, however, it’s generally a sign of affection, although sometimes your dog might lick you simply because you taste good.

Is Dog Licking Safe?

While it was once believed that dogs’ mouths were cleaner than those of humans and that dog saliva had healing properties, this myth^[2] has been thoroughly debunked. Considering that dogs are prone to nibbling on poop and licking their own unmentionables, it probably comes as no surprise that in reality, a dog’s mouth is a pool of germs. However, while dog saliva can carry such dangerous bacteria as Salmonella and E. coli, as well as parasites like Giardia and Cryptosporidium, these illnesses generally aren’t carried in quantities large enough to pose a danger to most humans, and there is very little evidence that doggie kisses are a means of transmission.

When Dog Kisses Aren’t Safe

Despite the low risk of the average person contracting an illness from dog licking, there are some people for whom the risk is too high to take a chance. Under no circumstances should your dog be allowed to lick anyone who falls into any of these categories, says Vetstreet^[3]: