Mouth ulcers may be related to liver function, and may also be related to trauma, lack of nutrition, low immunity, etc. Theoretically, the cause of the disease is not completely clear, and it is recommended to go to the hospital for specific examination and treatment. Poor liver function will be relatively poor body detoxification function, and low immunity, may often grow mouth ulcers. Mouth ulcers may grow after contact with hard foods or frequent lip biting. Deficiency of vitamin B₂ and vitamin B₆ are the most common causes of canker sores. Poor general condition with underlying diseases and low immunity of the body will also make the oral mucosa prone to break down and develop ulcers. Ulcers may be caused by a variety of factors of unknown etiology and may be related to liver, gastrointestinal, and renal function.