Nevus of Ota is a benign pigmented skin disease that invades the sclera and the skin of the trigeminal nerve distribution. The lesions are brown, blue or bluish-brown in color and range from a few centimeters in diameter to large patches, with large ones invading the unilateral or bilateral flanks. The disease occurs mostly in Asian people of color, and the incidence in China is about 16 per 1,000, more women than men (male to female ratio of 1:2, 67), most of them are congenital, and very few develop after adulthood. The pathological manifestation is that melanocytes that should be distributed in the basal layer of epidermis are lost in the dermis, forming unsightly pigmented spots. Nevus of Ota does not affect physiological health but is an aesthetic obstacle Although the lesions are extensive, Nevus of Ota is a benign lesion and generally has no effect on physiological health. However, because it is located in a prominent position on the face, it has a great impact on the image, so patients try every possible way to seek treatment. The principle of treatment should be to remove the pigment without leaving a scar. In the past, various treatments, such as freezing, skin grinding, skin peeling, radionuclide and herbal treatment, were not effective. Even surgical implantation or flap repair in plastic surgery left unsightly scars and the color of the implanted area would be inconsistent with the surrounding skin; only with the introduction of Q-switched laser technology did the treatment of nevus of Ota bring a new hope for complete cure. The new laser selects the laser wavelength as the absorption peak of melanin and adopts Q-switching technology to obtain great instantaneous power and very small pulse width, which acts on the melanin vesicles in melanocytes and causes melanocytes to break up. The broken cells and melanin, etc. are engulfed by phagocytic cells and transported through the lymphatic system and finally discharged through the kidneys. Since the wavelength of laser is extremely pure, the normal tissues without melanin absorb very little, and the extremely short pulse width ensures that the surrounding normal tissues are not damaged. Laser treatment for nevus of Ota is usually carried out once every three months and can be cured in 4-9 times. Generally, the darker the lesion is, the longer the treatment course is, but in the end, it can be completely cured without leaving a scar. No recurrence has been reported. Reactions after laser treatment of nevus of Ota: 1. After laser treatment of nevus of Ota, the skin will be slightly red, swollen, oozing and bleeding, and there is no need to bandage it. 2. After laser treatment of nevus of Ota, the next day, the red bleeding area will dry into black blood scab and swelling of different degrees will appear, and the blood scab will start to fall off on the 5th day. 3.After the scabs fall off, fresh, light pink, or black-red delicate skin can be revealed. 4.For shallow and light-colored nevus of Ota, pink and clean tissues can be seen after the first treatment, while for deeper nevus of Ota, black-red lesions can still be seen after the scabs fall off. 15 days later, pigmentation will gradually appear on the fresh skin, and the pigmentation will be most obvious in about 30 days. 5, a few people can appear obvious temporary hyperpigmentation or hypopigmentation, generally after a few months can be restored, very few darker color, can appear mild skin atrophy.