Syphilis is a sexually transmitted disease caused by infection with the spirochete syphilis. If you are allergic to penicillin, doxycycline or erythromycin can be given, but the treatment is less effective than penicillin. If you are pregnant, you can only choose erythromycin treatment, not doxycycline. Erythromycin and doxycycline treatment usually takes 15 consecutive days, and sexual contact should be avoided during the medication period, while both sexual partners need to be examined and treated together. After the treatment need regular review, generally after the first year of treatment, every three months review; after the second year of treatment, every six months review; after the third year of treatment review can be. If there is no change in the non-syphilis antibody titer, it is considered to be cured, and if the antibody titer rises, it is necessary to consider whether or not to re-treat.