The main reasons for thick lips are as follows: First, if the lips are tight and thickened within a short period of time, it means that there is an allergy to the lips, resulting in angioneurotic edema of the lips, mainly caused by contact with suspicious allergenic foods, drugs and cosmetics. Second, if the lips are slowly thickening, and the surface of the lips are chapped, flaking, erosion and other phenomena, is suffering from chronic lip inflammation, lip inflammation due to the stimulation of the external environment, such as dry, sun, cold, windy and the lack of nutrients in the body, such as lack of B vitamins, vitamin C and vitamin E, or people who have bad habits such as licking and biting lips, is easy to suffer from chronic lip inflammation. Third, lip ulcers, ulcers of the lip mucosa can lead to local mucosal redness, congestion, rupture and erosion, resulting in swelling and thickening of the lips.