Injections of benzylpenicillin for syphilis are effective. Syphilis is a chronic infectious disease caused by the syphilis spirochete, which is mainly transmitted through mother-to-child, sexual contact and blood. Clinical trials have demonstrated that the use of benzylpenicillin for the treatment of syphilis is clinically effective and the drug is safe. Benzathine penicillin is prohibited for patients with positive penicillin skin test, history of penicillin allergy, and allergic diseases such as asthma and eczema. Some patients may experience allergic reactions such as leukopenia, shock, gram-negative bacillus or Candida bifidus infection after use. It is recommended that patients with syphilis be treated with benzylpenicillin after eliminating contraindications under the guidance of a doctor to avoid the adverse consequences of blind use of the drug.