Onychophagia, or nailbiting, is a common oral habit, observed in both children and adults. The etiologies suggested for nailbiting include anxiety, stress, loneliness, imitation of other family member, heredity, inactivity, transference from a thumb-sucking habit, and poorly manicured nails. Treatment should be directed at the causes; punishment, ridicule, nagging and threats, and application of bitter-tasting commercial preparations on the nail are a variety of reminders, but are not appropriate approaches to treatment. The key to success is the nailbiter's consent and cooperation.