Patients with syphilis who are given three months of benzylpenicillin are cured in some cases and not in others, and need to be followed up for 2-3 years or more with syphilis serologic tests to determine efficacy. Benzathine penicillin is currently the first line of clinical treatment for syphilis, usually injected once a week for 3 weeks as a course of treatment. After 3 months of treatment, regular follow-up is needed for syphilis serologic testing to determine efficacy. Early syphilis is generally recommended to be followed up for 2-3 years, every 3 months after the first treatment, every 3 months thereafter, and every 6 months after one year. Late syphilis is followed for 3 years or more. The frequency of follow-up is the same as for early syphilis. The serologic examination of syphilis includes two major aspects: specific antibody and non-specific antibody. Specific antibodies include TPHA and TPPA, and non-specific antibodies include RPR and TRUST. Especially the titer of non-specific antibody RPR can reflect the degree of activity of the disease, and is also an indicator of the effectiveness of syphilis treatment. If after three months of treatment, the non-specific antibody titer of syphilis is detected to have more than a fourfold decrease or turn negative, indicating that benzylpenicillin has a definite therapeutic effect, and after that, the syphilis serology is regularly reviewed, and if there is no change in the titer in the follow-up for two years, and if the neurosyphilis and cardiovascular syphilis are ruled out, then it can be judged to be clinically cured. Whether or not a syphilis patient can be cured by three months of benzylpenicillin needs to be judged according to the results of syphilis serology, and it is recommended that the patient be treated with regular follow-up, so as not to delay the condition.