It is said that dogs lick their wounds because their saliva contain enzymes that can heal it.
This is only half true. For one, the healing enzymes in a dog's saliva is very small that the effect of it is minimal when it comes to cleaning and soothing the wound. However, it is believed that licking their wounds is the only way they are able to treat themselves reason why they do this.
Unfortunately, wound licking can even worsen the dog's wound-even turning it septic.