Your dog won’t just stop at his own wounds, however, and is likely to lick any grazes, cuts or injuries you may have sustained as well. Part of this is due to affection and their presumed duty of care towards you. Just like how your dog’s mother would have licked any wounds your dog sustained as a pup, your dog will try to care for you through licking if you have hurt yourself. There is also an element of your dog liking the taste of the fluid coming from the wound.
It is an instinctive response in dogs, humans, and other animals to attend quickly to wounds, and dogs are just one species that will lick at them to cleanse the area – cats, rodents, and monkeys do the same.
Although there are a lot of risks associated with letting dogs lick wounds, canine saliva does contain a few compounds that theoretically could help to disinfect and clean wounds. Additionally, the mechanical action of licking helps remove debris from the wound area, while cleaning it.
The following compounds are present in canine saliva and are thought to have antimicrobial and healing properties: Lysozyme and peroxidase enzymes help kill certain bacteria. Lactoferrin, defensins and cystatins are antibacterial. Opiorphin relieves pain. Thrombospondin is antiviral. Nitrate compounds inhibit bacterial growth. Protease inhibitor and epidermal growth factor help speed healing.
While there are some compounds in a dog’s saliva that help to clean wounds, your dog’s mouth is highly likely to contain a ton of bacteria which may cause you to develop an infection instead!
Unfortunately, although dog saliva does have some healing properties, the risks carried by allowing dogs to lick wounds are simply too high to warrant licking as a healing tool. When it comes to dogs licking their own wounds, a heavy amount of licking is likely to break down stitches and re-open any closed wounds, leaving them vulnerable to infection and the accumulation of dirt and debris. They can also damage their skin and develop hot spots from excessive licking, which introduces bacteria from the mouth into the deeper layers of the wound. This can significantly delay or stop wound healing and in the worst case scenario result in abscesses, cellulitis or more generalized systemic infections.