How long the treatment cycle of syphilis, and can not be generalized, with the course of syphilis and the use of drugs and so on. 1. early syphilis: often refers to the course of syphilis within 2 years, the preferred drugs for penicillin drugs. You can choose benzylpenicillin 2.4 million units of both sides of the buttocks intramuscular injection, once a week, a total of 1 ~ 2 times; or procaine penicillin 800,000 units / day, intramuscular injection, 15 consecutive days of medication. Penicillin allergic patients can choose ceftriaxone 0.5~1g, intramuscular injection or intravenous injection once a day for 10 days; or use doxycycline 100mg twice a day for 15 days. 2. Late syphilis: often refers to syphilis with a disease duration of more than 2 years, the preferred drug is still penicillin. Benzathine penicillin 2.4 million units can be injected intramuscularly into both buttocks, once a week for 3 times; or procaine penicillin 800,000 units/day, intramuscularly injected, 20 days of continuous medication for a course of treatment, the effect of the poor can be separated for 2 weeks after the interval, give the second course of treatment. Penicillin allergic patients can use doxycycline 100mg, twice a day, for 30 days. In addition, patients with cardiovascular syphilis, patients with neurosyphilis or patients with fetotransmitted syphilis may differ in drug selection and dosage. Therefore, patients with syphilis are advised to go to the hospital for examination as soon as possible, and follow the doctor’s instructions on the choice of medication and the specific treatment cycle according to their personal situation and the degree and type of the disease.