Erythromycin is generally not used to treat syphilis due to the drug resistance of the syphilis spirochete, and the drug of choice for the treatment of syphilis is penicillin. Clinically, erythromycin is mainly used to treat scarlet fever, tonsillitis and gonorrhea caused by streptococcus bacteria, and can also be used to treat syphilis, soft tissue infections and other conditions. Erythromycin is a macrolide antibiotic with strong inhibitory effect on gram-positive bacteria such as staphylococcus and Streptococcus pyogenes; it also has a certain inhibitory effect on gram-negative bacteria such as gonococcus and spirochetes; the mechanism of action is mainly to inhibit the synthesis of bacterial proteins so as to achieve the effect of antibacterial. But penicillin is the first choice for the treatment of all stages of syphilis, commonly used drugs are benzylpenicillin, procaine aqueous penicillin G and so on. In case of allergy or intolerance to penicillin, erythromycin, tetracycline, ceftriaxone and other drugs can be considered instead. If the patient is diagnosed with syphilis, it is recommended to seek medical treatment in a timely manner, do not blindly take medication on your own, so as not to delay the condition. Keep a positive mindset, follow the doctor’s instructions, and use medication scientifically.