Syphilis and AIDS, between the two, AIDS is more serious. This is because AIDS currently cannot be cured, and requires long-term regular intake of antiretroviral drugs. Syphilis, on the other hand, can be completely cured. In the early stages of syphilis, such as primary and secondary syphilis, the treatment is often very effective and also very convenient. Generally, a treatment course of two to three weeks can cure most syphilis infections. Therefore, between syphilis and AIDS, AIDS is more serious. These two diseases often occur simultaneously because both are transmitted sexually.