To understand which sexually transmitted diseases (STDs) are curable, we first need to look at their pathogenic, disease-causing origins. The most common STDs are viruses, bacteria, parasites and protozoa. Among these, bacterial and protozoan STDs such as chlamydia, gonorrhea, syphilis and trichomoniasis are readily curable, and have been since the development of antibiotics. In fact, one of the first antibiotics to be developed was Salvarsan, an early treatment for syphillis that also gave us the term “magic bullet” based on its effectiveness.