The principle of laser removal of nevus of Ota is as follows: 1. Stimulate the proliferation of collagen: When the dye pulse laser stimulates and destroys blood cells and blood vessels, it will cause a slight inflammatory reaction, thereby stimulating the proliferation of dermal collagen. Once the menstruation is eliminated and the body absorbs and disappears, the purpose of treatment can be achieved. 2. Destroy blood cells and blood vessels: The dye laser is a pulsed laser with a wavelength of 595nm and a bandwidth of about 450?s to 40ms. The main treatment target is hemoglobin in the red blood cells in the blood vessels, because hemoglobin can strongly absorb the dye laser. The wavelength causes the temperature in the blood vessels to rise sharply, causing burns and damage to the blood vessel walls. The damaged blood vessel wall cells are absorbed and disappeared by the body, thus achieving the purpose of treatment. Everyone already understands the principle of laser removal of nevus of Ota. In order to ensure the safety and effectiveness of the surgery, we remind you to choose a regular medical plastic surgery institution and experienced experts to perform nevus of Ota removal surgery.