A study [subscription required] published in July gave us cause to lick our wounds, as Dutch researchers found compounds in human saliva that hasten healing. While the simple proteins called histatins are well known for their ability to ward off infections, biochemist Menno Oudhoff of the University of Amsterdam discovered a subset of histatins that also prompt cells from the skin’s surface, called the epithelium, to close over a wound. “The first thing that needs to happen for wound healing is to activate the migration of epithelial cells,” Oudhoff says.

The healing powers of saliva have long been suspected, because lesions inside the mouth mend more quickly and scar less than wounds on the skin. Researchers had ascribed that benefit to complex compounds known as growth factors. When Oudhoff applied human saliva to skin-cell cultures scratched by a needle, however, he found that the concentrations of growth factors were too low to have any therapeutic effect. But he did isolate another group of simple salivary compounds—the histatins—that caused epithelial scratches to close up to twice as quickly as normal.

This finding is good news for clinical medicine because histatins are both cheaper to make and more easily purified than growth factors.