Everyone knows that when a dog is excited, they’ll wag their tag. When a pooch is angry, they’ll likely bare their teeth and growl. And when your dog wants to show you just how much they love you, they’ll usually give you kisses — a.k.a. they’ll lick you affectionately.

While most pet owners love and encourage these kisses, there’s a lot of debate among doctors about whether or not it’s SAFE for your dog to lick you, particularly on the face.

You might have heard from some people that “dogs mouths are cleaner than humans,” while other adages say dogs can carry diseases on their tongue. So, what is actually happening when your dog licks your face? Is it safe or does it matter at all? Here’s the truth.

For starters, allow us to officially debunk the thought that your dog’s mouth is cleaner than your own — in reality, both dog and human mouths are pretty darn gross. It’s tough to compare the two though because they’re vastly different environments. Both pups and people have hundreds of different types of bacteria in our mouths, but we only share 16% of the same types of bacteria.

Worse, studies have shown that the transfer of bacteria from a dog mouth to a human mouth (most likely done by a dog licking a person in the mouth) can have negative repercussions for the human.

Dog saliva in a human mouth has been shown to cause disease like gingivitis, periodontitis, or porphyromonas gulae — that last one can cause inflamed gums and tooth loss. The disease is incredibly rare in humans, but common in dogs, and 16% of dog owners have caught it from letting their dogs lick their face.

Even more extreme would be if your dog licked your mouth and there was an open wound. Say you bit your cheek or had some bleeding gums from brushing too hard, the bacteria from your dog’s tongue could enter through those cuts and cause infection deeper in your body.

Many of these potential diseases are, as we mentioned, common in dogs and not humans. However, that brings up a serious issue. Human bodies will have a harder time fighting off anything you might catch from your pup since our immune system hasn’t been taught to fight these illnesses.

And guess what? That works both ways.

We have bacteria in our mouths that canine bodies are not used to experiencing, so a kiss on a mouth could affect your pet, too. But despite all these opportunities for potential danger, experts have concluded that mouth-to-mouth contact with your dog is not too dangerous. We both have bacteria in our mouths, after all, so the chances of contracting these diseases are slim.

So, if you’ve ever felt skeeved out by pet owners who love to smooch their pooch, your heebie-jeebies are warranted. We can all rest easy though, knowing that an accidental show of affection is very unlikely to harm you or your pet.