Why Do Dogs Smell Open Wounds

While playing with your dog in the park, you slid on some wet grass, getting a scrape on your knee. Your dog, ever the faithful companion, bounds over to you – and starts sniffing, and even licking, at the wound! You shoo them away, but you can’t help but notice that every time you get a cut or scratch (even if you’ve gotten more serious wounds) the first thing your dog does is come up to sniff the injury. This happens when your pup gets a cut or scrape on themselves, too! They often sniff and lick the wound, sometimes obsessively. If they have other dogs around, they may demonstrate this behavior with their companions as well. Why does your dog do this? Is it good for your dog to sniff your wounds? Do they just smell blood, or is it something more than that? We’re going to go into dog-sniffing behavior and all the things that go along with it in this article. 

There are some conflicting theories as to why dogs sniff each other’s wounds, your wounds, or the wounds of people in their human “pack.” The most prevalent is that dogs use their noses to communicate – they sniff each other in greeting, and it’s thought that different dogs give off different smells depending on the hierarchy of their group. Dogs also have an incredibly strong sense of smell, approximately 1 million times greater than ours, and this sense is often connected to the “sixth sense” that we owners think our dogs have. They notice things we don’t – because they can smell them!

When dogs are sniffing your wounds, it’s likely deeper than them simply smelling the blood and being interested. Dogs can smell things called volatile organic compounds (VOCs), which are often given off by people who have cancer. They can detect high blood sugar, unusual compounds in the skin (such as with tattoos), and bacteria in the blood that could cause infection. Evolving this behavior likely helped keep their pack healthier by allowing all the animals to tend to each other’s wounds and keep tabs on their overall health. And a healthy pack is one that’s well-fed and well-defended, so it’s worth it!

As dogs grew to live with people, they extended their pack-preserving behavior to us. After all, we’re now part of their “family,” and we’re a major provider of their health, comfort, and food. So, keeping us healthy and happy is as important as keeping the other animals in their pack healthy and happy! For the same reason that mother dogs constantly sniff and lick their babies, your dog sniffs and licks your wounds, the wounds of the other animals in the home, and possibly even the wounds of strangers, if your dog is a more sociable animal. But while sniffing the wounds is generally accepted, there’s some question as to whether the behavior that tends to follow – licking the wounds – should be encouraged. 

It’s not necessarily bad for dogs to sniff their own open wounds or the wounds of others. As mentioned previously, dogs have incredibly strong senses of smell and can detect when something’s wrong often before we can. This behavior is instinctive and hard-wired into your pet’s DNA and would likely be difficult to prevent. However, there is some debate as to whether or not dogs should be allowed to lick wounds. While the act of licking wounds can be helpful in loosening surface debris and cleansing deeper debris from an open cut, says Stanley Coren, Ph.D, and studies have shown that there are simple proteins called histatins in animal saliva which are well-known for their ability to ward off infections, not everything located in your dog’s saliva is great for you. Dog saliva, unfortunately, has been shown to carry dangerous bacteria like Pasteurella, which can cause infections when introduced to open wounds. 

So, while your dog sniffing at wounds is acceptable and even welcome, behavior, you shouldn’t encourage your dog to lick your wounds, their wounds, or anyone else’s. We would recommend gently turning your dog’s head away after they’ve sniffed at a wound so that they learn not to lick the area. If it’s an open wound on your body, you could also disinfect and wrap it before allowing your dog to sniff where the wound is located; this will give your dog the satisfaction of being able to inspect your wound and make sure you’re okay, while preventing them from introducing potentially harmful bacteria through licking.

The only exception to the rule of disallowing your dog to sniff and/or lick wounds may be with mother dogs with new puppies. The specific, intimate bond that’s being created between a mom and her pups is not something you will want to disrupt unless you notice specifically that the behavior is having adverse effects on the puppies themselves. You also may want to allow your animals to sniff and lick each other’s superficial wounds, as these carry less chance of getting infected and allow for bonding between your pets. And of course, you do not want to curtail your dog’s natural inclination to sniff – that will just lead to confusion for your pooch!

Wound-sniffing dogs are the focus of several studies to see how their particular talent for discovering infection or disease can be put to use in a more clinical setting. Your dog’s nose knows more than we ever will! So let your dog sniff away, but discourage your pet from licking deep wounds – you don’t want to get an infection from your dog when all they’re trying to do is prevent you from getting hurt.