For the treatment of moles, surgical excision and laser “spot” moles are commonly used. The choice of treatment method generally takes into account several factors: 1. size: moles with diameter <5mm can be treated by laser and the scars are not obvious, otherwise they can be removed by surgery. 2. Depth: Some moles that do not protrude are often deeper, so if laser treatment is used, it is easy to leave a deeper pit, so you can choose surgery. On the contrary, some moles that protrude from the skin surface can be treated with laser. 3.Site: Moles on the palms of hands, soles of feet, under finger (toe) nails, lips and external genitalia have the possibility of malignant transformation, so they can be removed prophylactically. 4.Nature: Only if the mole is clearly benign can the laser be used to "spot" the mole, because the mole that has been "spotted" cannot be used for pathological examination. If the benign or malignant nature of the mole is not clear, it is also recommended to take surgery and send the cut mole for pathological examination after the surgery. The most commonly used laser for blemish removal is the ruby laser. The light wave of this laser targets mainly black and brown pigments. The pigments are absorbed by the laser and broken down, and as the pigments are gradually absorbed by the body, the color of the spots fades. After the laser treatment, the skin becomes white, no blood oozing, and no scarring is left after the scabs fall off. Moles, tattoos and eyebrow tattooing all belong to this type of pigment. Vascular pigmentation such as cutaneous hemangioma can be treated with dye laser. The hemoglobin in the blood vessels absorbs the laser and generates heat to shrink the microvessels, and the skin gradually returns to normal. Skin capillary hemangioma with larger area should be treated in small amount and several times, otherwise obvious symptoms such as edema, blister, pain and fever will appear locally. There are the following kinds of spots and moles suitable for laser treatment. 1.Freckles, mostly small brown spots with the size of a needle point to rice, mainly on the cheeks and around the bridge of the nose, are usually found at an early age and accompany people throughout their life. 2.Nevi, which appear gradually after puberty, ranging from several to dozens, especially on the face and neck, are brown or black, pinpoint to rice, flat or raised on the skin surface, and deepen in color with age. 3.Mother Ota's spots, most commonly found on the upper part of one side, present gray-blue patches with different shades of color and deep pigmentation to the dermis, and the sclera of the eye can also present gray-blue. 4.Age spots are several or dozens of wax-like rough brown papules or patches, gradually larger in size, more common on the face and back of hands. 5.Sun spots are easily found on exposed parts such as face, forearm, calf, etc., with brown patches. Liver spots appear symmetrically on both cheeks, with false pig liver color, but they are not related to liver disease. 6. Tattooing and eyebrow tattooing are artificially planted pigments in the dermis, or accidental injuries that cause ink, pencil cores, iron ends, etc. to enter the skin. The above mentioned moles can be removed by laser and often require multiple treatments, the deeper the color depth, the more treatments are needed. The deeper the pigmentation, the more treatments are needed. The mother of Ota pigmentation is present in the dermis and treatment takes longer. Because the laser energy is limited, it is not possible to penetrate deep into the area at one time. Therefore, the treatment starts with the surface pigment gradually becoming lighter after receiving the laser, and then the next laser treatment will be performed after 3 months. For lighter freckles and coffee spots, generally one laser treatment can remove the pigment, but it cannot prevent recurrence. Only congenital birthmarks will not recur after treatment. The pigments of tattoos are found in the dermis and require several laser treatments to be effective. The number of treatments needed to achieve optimal results depends on the size, location and depth of the pigmented lesion. The usual interval between treatments is 4-8 weeks, which allows the body to remove the maximum amount of pigment. After each treatment, the pigment is gradually removed and the skin tone gradually lightens. Black tattoos require 2-3 treatments, coffee spots require 3-4 treatments, melasma requires 4-6 treatments, and nevus of Ota requires 7-9 treatments.