The appearance of black spots on the waist may be caused by hyperpigmentation, pigmented nevus, black lesions and other factors. 1. Hyperpigmentation: if there is a history of sun exposure on the waist before the occurrence of black patches on the waist, then it should be considered to be caused by hyperpigmentation, and such people should do a good job of sun protection, and generally do not need special treatment. 2. Pigmented nevus: black patches on the waist may also be caused by pigmented nevus, which is composed of benign proliferating melanocytes, with clear boundaries with the surrounding tissues, regular edges and uniform color, and can be treated by surgery or laser. 3. Black lesions: black patches on the waist may also be caused by black lesions, less common, which is a pigmentation disease that occurs in the skin and mucous membranes, and the surface of the patches will be covered with dust-like skin debris, and you should pay attention to maintain a happy mood, and you can use vitamin C, tranexamic acid tablets and other drugs for treatment. There may be other reasons for the appearance of black plaques on the waist, it is recommended to go to the hospital in a timely manner to clarify the cause of the disease, the above drugs should be used under the guidance of a doctor.