Most patients with syphilis have no symptoms on the tongue, and some patients with stage 2 syphilis may have mucous membrane spots, erosions, and ulcers on the tongue. Syphilis is an infectious disease caused by syphilis spirochete infection, which is mainly transmitted through sexual contact. In the early stage, it mainly invades the skin and mucous membranes, and in the late stage, it can invade blood vessels, the nervous system, and organs of the whole body. Acquired syphilis is categorized into stage I, stage II and stage III syphilis. In stage II syphilis, tongue symptoms may appear, commonly manifested as vesicles, red infiltrating patches on the dorsal part of the tongue, ulcers and so on. When diagnosed with syphilis, follow the doctor’s instructions for early, adequate and regular treatment, and avoid stopping or reducing the medication on your own. Maintain a healthy lifestyle, avoid unclean sex, and avoid cross use of personal belongings with others.