Pigmented nevus, also known as nevus, is a pigmented spot, patch or nodule formed by nevus cells on the body surface. The larger, warty pigmented moles that protrude from the body are commonly called “nevus”. In folklore, there is often the saying that a certain part of the “mole” is the main “blessing” or the main “curse”, but in fact are not scientific. The medical treatment of pigmented moles is from the perspective of aesthetics and prevention of malignant change. Larger and more pigmented moles on the face obviously affect aesthetics and usually need to be removed. Pigmented nevi on friction areas of the body, such as palms and feet, as well as on mucosal surfaces, are recommended to be removed as soon as possible because of their high tendency to malignant transformation. It has become a popular consensus that pigmented moles have the possibility of malignant transformation. However, not all pigmented nevi will become malignant. What are the signs of malignant pigmented nevus? If a pigmented nevus shows any of the following conditions, it is a sign that malignancy is about to occur or has already occurred, and should be treated as soon as possible. These include: rapid growth of pigmented nevus or significant thickening although there is no obvious change in the size of the nevus; color change, deepening of color, especially the appearance of light blue hue; hair loss, crust removal or satellite foci; surface breakage, bleeding, ulceration; itching or painful inflammation and other unexplained symptoms. Regardless of the purpose of treating pigmented nevi, the principle of “either no treatment or complete treatment” should be followed. As far as possible, small congenital moles should be removed prophylactically. For dark spots on the hands and feet, especially those appearing after the age of 30, they should be removed. At present, some patients are afraid of “open surgery” and are willing to receive laser treatment for pigmented moles. However, lasers are not suitable for pigmented nevi, and the treatment is not complete and can easily recur. Early melanoma and pigmented nevus are not easily distinguished by the naked eye, and blind laser treatment can lead to the spread of lesions. In China, there are reports of laser treatment leading to the spread of melanoma, and the lesson is very profound. Drugs and freezing can also be applied, but only for lesions less than 3mm in diameter. For pigmented nevi with a diameter of 4mm or more, surgical excision must be adopted.