It is the first skin and mucous membrane damage that occurs after syphilis infection, and is a typical clinical manifestation of stage I syphilis. Most of them are solitary, usually in the genital area, such as the inner foreskin and the glans, and are round or disc-shaped ulcers, 1-2 cm in diameter, clearly demarcated from the periphery, with neat edges, dyke-like elevation, cartilage-like hardness when touched, no pain or tenderness, flat, and with a little exudate at the base. Syphilis spirochete testing of the secretions and serology for syphilis can be done. Treatment with long-acting penicillin, such as benzathine penicillin, is administered intramuscularly for a relatively long period of time, and the course of medication is determined by the degree of symptom relief and serologic testing. For penicillin allergy, tetracycline and macrolides may also be considered as alternatives.