White vertical lines on both sides of the tongue are considered to be caused by dental friction, followed by the possibility of tongue lichen planus, oral white keratosis and other diseases. 1. Teeth friction: normal people will not appear white vertical lines on both sides of the tongue, but if you have the habit of grinding teeth, the local friction by the teeth, may leave vertical lines, is a normal situation, do not need special treatment. 2. Tongue lichen planus: tongue lichen planus is a kind of chronic inflammatory disease of the skin mucosa, the cause of the disease is mostly related to infection, mental nerve, endocrine and other factors, which will lead to white vertical lines on both sides of the tongue. 3. Oral white keratosis: oral white keratosis can also lead to patients with white vertical lines on both sides of the tongue, the cause of which is caused by mechanical friction or chemical stimulation, common smoking, betel nut chewing, stumps and so on. The causes of white vertical lines on both sides of the tongue are many, and it is recommended that patients go to the hospital for relevant examinations to make a clear diagnosis after eliminating physiological factors. If there are bad teeth grinding habits, they should be corrected in time.