The difference between AIDS oral cavity and syphilis oral cavity mainly lies in the disease etiology, clinical manifestations and other aspects. 1. Disease etiology: syphilis patients are mainly infected with syphilis spirochetes, caused by local oral mucosal symptoms. AIDS patients are mainly low immunity, resulting in external pathogens are more likely to infect the oral cavity, causing Candida albicans infection, periodontal disease. 2. Clinical manifestations: the symptoms of syphilis oral lesions are mainly erythema and pustules on the oral mucosa, which may be accompanied by erosion. In severe cases, syphilitic dendritis may appear, and irregular horseshoe-shaped ulcers may appear, causing patients to have difficulty in pronunciation and swallowing. And AIDS patients with their immunodeficiency, resulting in the body is more susceptible to infection with a variety of pathogens, such as Candida albicans infection of the oral mucosa will appear white-yellow spots, periodontal disease will lead to erythema at the gums, bleeding and other symptoms. In severe cases, the manifestations of Kaposi’s sarcoma can appear in the oral cavity, such as large plaques and nodules on the oral mucosa, and the surface can be broken. Patients suffering from AIDS or syphilis, if oral lesions appear, it is recommended that they go to a regular medical institution for timely medical treatment to prevent the development of the disease and adverse effects.