For syphilis patients, it is not clinically certain that the patient can be cured of syphilis by applying a few penicillin. The first example is benzathine penicillin, which is usually injected intramuscularly once a week, once with 2.4 million units, three times for a course of treatment. Patients need to continue to apply penicillin until their titers can be controlled at about 1:4 before they can stop the drug for observation. The duration of application varies from patient to patient, with some patients being able to stop after just a few injections; others may have repeated injections for months or even half a year before their titers are slowly brought under control. Even if the titer is controlled at about 1:4, the patient is not completely cured of syphilis. The patient still needs to enter a long clinical titer observation period, which takes about three years. If it is determined that the patient’s titer does not rise again and neurosyphilis and cardiovascular syphilis can be ruled out, then the patient can be considered cured.