Latent syphilis is also known as latent syphilis. After infection with syphilis spirochetes, the patient can have various symptoms, at this time is the dominant syphilis, if untreated, improper treatment method or inadequate treatment dose, incomplete treatment, although the syphilis symptoms have disappeared, but the syphilis seropositive; or after infection, the patient has never shown any symptoms, only in the physical examination, pregnancy test or marriage test found positive syphilis seropositive, this kind of patients are latent syphilis patients. Although asymptomatic and healthy in appearance, syphilis spirochetes are still present in the body and can produce symptoms when resistance is reduced, and they are also somewhat infectious, especially early latent syphilis. Infection within 2 years is called early latent syphilis, and these patients have the possibility of second stage recurrent damage at any time, so they should be considered infectious. Those who have been infected for more than 2 years are called late-stage latent syphilis, and relapses are rare in these patients and are generally considered not contagious, but if a female patient is pregnant, she can still pass the placenta to her fetus and develop fetal syphilis. If latent syphilis is not treated properly, some patients may eventually develop advanced syphilis and severe damage. Untreated latent syphilis will have the following outcomes: 1. Clinical symptoms appear after a certain period of time. Early latent syphilis often occurs with recurrent stage II syphilis damage and is infectious. Late latent syphilis then occurs as a tertiary syphilis manifestation with cardiovascular and central nervous system symptoms; 2. Birth of congenital syphilis children, especially early latent syphilis. Therefore, RPR titers should be checked regularly before and during pregnancy, and those found to be positive should go to the hospital for evaluation to have another child; 3. Remain positive for a long time without symptoms and remain latent for life; 4. After several decades, the serologic reaction naturally turns negative and is also asymptomatic, reaching natural cure. The latter two endings are not serious but are not rare in clinical practice. It is more common to see the first two. Therefore, once latent syphilis is detected, please go to the hospital promptly to seek medical attention.