Cracking at the corners of the mouth is clinically manifested as bilateral chapped corners of the mouth area, sometimes becoming pale by saliva infiltration, due to the following reasons: first, long-term nutritional imbalance, lack of vitamin B and other causes of orofacial infection; second, when dental loss occurs in elderly patients, the vertical distance between the upper and lower jaws is shortened, saliva often overflows and gathers in the corners of the mouth, leading to bacterial, fungal or viral infection and orofacial infection; third, applying or contacting cosmetics such as lipstick, causing allergic inflammation resulting in corners of the mouth cracking; fourth, when performing oral treatment, inadvertently damaging the corners of the mouth or being hit by foreign objects causing corners of the mouth cracking.