Blackening of the anus is a relatively common phenomenon in the clinic, with the growth of age will gradually darken the color, most commonly seen in hyperpigmentation. If there is no itching or special symptoms, it is a normal physiological phenomenon, no need to apply special drugs or methods to intervene, can be clinically observed. For some of the anus blackened with swelling or eczema-like changes, it is possible to consider the possibility of infectious molluscum contagiosum or anal eczema. Molluscum contagiosum can be treated by applying ointments such as the common Euthyrox and interferon ointments. In more severe cases, they can also be completely eradicated by laser surgery or liquid nitrogen freezing. Therefore, it is best to go to a regular hospital for a detailed examination, and you can go to the dermatology department for the appropriate examination to find the exact cause of the disease and take the appropriate treatment plan.