There’s a hint of blood in your mouth after you’ve bitten your lip or tongue. You lick it away, but then you think: “What happens if I lick blood?”

Don’t worry. Blood doesn’t contain any harmful bacteria or germs that can make you sick, according to the U.S. Centers for Disease Control and Prevention (CDC). But if you have an open wound or sore on your tongue, you should resist the urge to lick it because of the risk of infection.

“The longer you leave it there, the more likely it is that something will happen,” said Dr. Michael Baudry, an assistant professor at Tulane University School of Medicine in New Orleans who has researched germs in saliva.

The CDC says more than half of all children have had an ear infection by age 3, and more than one-third of adults in the United States get an upper respiratory infection each year. Blood was present in about 7 percent of these cases — which include colds and runny noses — according to a 2013 study published in Clinical Infectious Diseases journal.

Another study found that people who spit into their hands before shaking hands may transfer bacteria from their mouths into those.

Last modified: September 5, 2022