One side of the face is big and the other side is small, which may be caused by heredity, dietary habits and other physiological factors, and generally do not need to take special treatment. If it is caused by mumps, occlusal hypertrophy and other diseases, you need to take medication or surgical treatment for the cause of the disease. 1. Physiological factors: Heredity, or long-term use of one side of the chewing food, may lead to one side of the face is large and the other side of the face is small. Generally, this kind of situation will not cause any harm to the body, and no special treatment measures are needed. You need to correct bad chewing habits in daily life, and most of them can be relieved. 2. Mumps: A large face on one side and a small face on the other can also be caused by mumps. Patients can follow the doctor’s instructions for intravenous infusion, such as ribavirin and other antiviral drugs, and physical cooling can be taken when high fever. Generally after standardized treatment, the symptoms can be improved. 3. Bite muscle hypertrophy: one side of the face is big and the other side is small, also considered to be due to bite muscle hypertrophy. Patients can follow the doctor’s instructions to inject botulinum toxin, which can reduce the size of the bite muscle. Or take bite muscle partial excision, jaw angle osteotomy and other treatment measures. There are many reasons that cause one side of the face to be big and the other side to be small, and it is recommended that patients go to a regular hospital to find out the cause of the disease.