Health risks of nail biting linked to high bacterial counts

Nail biting is a common behavior, affecting between 20 and 30 percent of Americans according to the Cleveland Clinic. It is often used as a coping mechanism to provide a sense of calm during periods of boredom or stress.

From a health perspective, the practice introduces significant amounts of bacteria into the mouth. Research from the University of Pennsylvania and Johns Hopkins University indicates that the area under the fingernails, known as the subungual space, contains the highest concentration of bacteria on the hand. One study found that these spaces averaged approximately 245,000 colony-forming units, a significantly higher number than other parts of the hand. Additionally, research from Atatürk University suggests that biting nails increases the presence of bacteria within the oral cavity.