Syphilis ate doxycycline a month serious, may be the use of doxycycline treatment is ineffective, at this time should be immediately discontinued, in the case of penicillin is not allergic to the use of penicillin treatment; may also be the long-term use of doxycycline caused by adverse reactions, it is recommended to stop the drug in time to see a doctor. Penicillin is the drug of choice for the treatment of syphilis, often using benzylpenicillin, procaine penicillin, etc. Penicillin treatment can inhibit the synthesis of the syphilis spirochete cell wall, blocking the reproduction of syphilis spirochetes, thus killing the syphilis spirochete. If the patient is taking oral ciclosporin for a month, the symptoms are serious, it is recommended to stop the drug immediately, if the penicillin is not allergic to, under the guidance of the doctor to use penicillin treatment, the routine use of benzylpenicillin 2.4 million units, intramuscular injections, the course of treatment according to the course of the syphilis varies. If you are allergic to penicillin, doxycycline treatment is ineffective, can be under the guidance of the doctor full course of treatment with ceftriaxone sodium. In addition, taking doxycycline for a month syphilis serious, may also be long-term use of doxycycline caused by adverse reactions, such as drug rash, liver function abnormalities. It is recommended that patients stop taking the drug in time and go to the regular hospital to improve the examination and symptomatic treatment under the guidance of the doctor. The treatment of syphilis should be carried out under the strict guidance of the doctor, and if there is any discomfort, consult a doctor in time.