To prevent lip cancer, one should develop correct dietary habits, eat less betel nut, tobacco and alcohol; women should minimize the use of cosmetics that come into contact with the lips, such as lipstick; and avoid exposure to strong light to prevent lip stress. It should also enhance the body’s resistance, eat more vegetables and fruits, and take vitamins in moderation. Habitual lip biting will stimulate the lip gland and induce cancer. For children who habitually bite their lips, parents can apply edible bitter substances on their lips or wear preventive devices; adults should rely on perseverance to overcome this bad habit.