Long-term oral ulcers may be related to systemic diseases and systemic diseases, as follows: 1. Aphthous stomatitis: more recurrent oral ulcers, which may be related to the body’s immune dysfunction, exertion, fire, tension, etc., but there is usually no need to worry too much; 2. Leukodystrophy: a systemic disease in immunity, which can involve the oral cavity, vulva, eyes, internal organs, central nervous system. Immune small vasculitis lesions need to be taken seriously; 3, connective tissue disease: especially systemic lupus erythematosus, often with oral ulcers, can be combined with other skin damage, but also fever, pain, kidney and blood lesions, is a systemic disease; 4, aspergillosis; 5, tumors: some malignant tumors, including blood system diseases, may cause long-term, recurrent oral ulcers, need to do systematic examination to clarify.