Examining saliva’s healing powers
Q. I saw a movie where someone got a small burn and was told to spit on it to make it heal faster. Does saliva have curative powers?
A. When a dog is injured, the first thing it does is lick its wounds. Should we be doing the same? The answer is a little complex.
You may think of saliva simply as lubrication for your tongue or a good adhesive for spitballs, but it’s a surprisingly active substance with immune properties. It contains immune cells, antimicrobial and antifungal proteins, and growth factors that promote wound healing. “There’s a medicinal value in saliva that’s not appreciated,’’ explains David Wong, a saliva expert and director of the Dental Research Institute at University of California Los Angeles. That helps explain why a burn or cut in your mouth will heal five times faster than a similar wound on your skin, and won’t leave a scar.
But there’s a counterpoint to saliva’s healing properties, says Frank Oppenheim, chair of oral biology at Boston University Henry M. Goldman School of Dental Medicine. Bite wounds are notorious for their potential to cause nasty infections; the saliva that is so healing in the mouth can carry disease if exposed to an open wound on the skin. That’s because saliva’s other component is bacteria that live in the mouth, which are very different from the bacteria normally found on the skin. “If you bring oral bacteria to the skin,’’ he says, “the skin may not have the resistance to overcome infection,’’ particularly with something more than a superficial burn.
Studies in other mammals show that licking burns and wounds promotes healing, and this has led scientists to try to identify specific components of saliva that can be used to treat burn victims. But no one has conducted the same study in humans. So for now, you’ll have to spit at your own risk.
Correction: Because of a reporting error, an earlier version of this column gave the wrong affiliation for Dr. Frank Oppenheim. He is chair of oral biology at Boston University Henry M. Goldman School of Dental Medicine.