Part of the show Social Insects, Biting Bugs and a Potted History of Honey
Greg in Denmark asked:
Although saliva is used to start the process of breaking down food, I was wondering if saliva has any healing properties. Cats lick their wounds, and often people instinctively suck small cuts on the backs of their hands. So does saliva keep wounds germ free and help them heal up quicker?
Yes, saliva does have some beneficial properties because it contains a number of proteins. Those proteins include antibodies, and we make a lot of antibodies when we are infected with various things, and they can mop up bugs and viruses. That's one bonus of saliva. It also contains another protein called lysozyme, and this is an enzyme that can break down some types of bacterial cell walls. When you lick something that has bacteria on it, those lysozymes attack the bacteria and help to neutralise them. Antibodies and lysozyme are also in your tears. Also in your saliva is mucus. Mucus is a protein that forms a sort of meshwork, and it traps things and stops them moving away too fast. So yes, saliva does have a medicinal role too.