In recent years, the negative effects of UV rays on the skin have become more and more evident in our daily lives, both in the advertisements of sunscreen and skin care products and in lectures on skin beauty care, such as loss of moisture and elasticity, resulting in dry and rough skin, aging skin, wrinkles, abnormal pigmentation, and so on. However, what I want to share with you today is some of the principles and uses of UV light as a common dermatological treatment, so that you know that UV light is not really “useless”. Let’s take a look at the positive effects of UV light! 1, let’s look at its germicidal effect with ultraviolet light irradiation of infected wounds, can directly kill pathogens or change the living environment of microorganisms to inhibit their growth and reproduction. The germicidal effect of UVC is related to its wavelength, different wavelengths of UVC germicidal ability varies. 250~260nm is the strongest, and later reduced, the sensitivity of various bacteria to different wavelengths of UVC varies. In addition, UV radiation must reach a certain irradiation intensity to have an effective germicidal effect. 2, promote the role of vitamin D synthesis This is an important physiological role after UV radiation skin, which not only has a preventive and therapeutic effect on rickets and chondromalacia, but also has positive significance for the prevention of osteoporosis in the elderly. 3.Promote local blood circulation role of ultraviolet radiation area vasodilation, improve blood circulation, can make inflammatory mediators to accelerate the clearance, hypoxia and acidosis situation is alleviated. 4.Anti-pain effect Erythema amount of UV treatment has obvious analgesic effect. It has good relief effect on both inflammatory and non-inflammatory pain. 5.Anti-inflammatory effect The above-mentioned bactericidal effect, promoting local blood circulation and analgesic effect are all beneficial to the anti-inflammatory effect. In addition, UV can mobilize and strengthen the body’s immune function to clear the role of pathogens more quickly. 6.Promote wound healing effect Ultraviolet light has the effect of promoting cell growth, division and proliferation as well as improving blood circulation, improving tissue cell nutrition and regeneration conditions, etc., which are conducive to wound healing. Clinically, it can be used for the treatment of various infected wounds, prolonged wounds and skin ulcers, etc. 7, pigmentation role of ultraviolet light caused by pigmentation is conducive to both enhancing the sun resistance of the skin, improve the resistance to ultraviolet light, but also the mechanism of action for the treatment of vitiligo. PUVA method is commonly used clinically, that is, oral or topical photosensitizer after receiving UVA irradiation treatment. 8, skin keratin thickening UV irradiation can induce skin keratin thickening, up to 2~3 times thicker, thus enhancing the barrier role of the skin and reducing the penetration of harmful chemicals and allergens into the skin. In addition, a certain intensity of UV radiation on the body surface can cause skin pigmentation, keratin thickening, and skin barrier defense ability; it can also strengthen the body, improve the ability to adapt to environmental changes and resistance to certain diseases, for example, it can be used to prevent pressure sores, folliculitis, boils, etc. 9, desensitizing effect Under repeated UVB irradiation, the body will produce a small amount of histamine, which continuously enters the blood from the skin and stimulates histaminase production, and when the latter has sufficient amount, it can break down the excess histamine in the blood during allergic reactions, and play a desensitizing effect. In addition, UVB irradiation has been reported to significantly relieve the itchy skin symptoms of AIDS patients, which is conducive to the improvement of patients’ survival quality. UVB also has the effect of promoting apoptosis of tumor cells, etc. There are many positive effects of UVB, so let’s learn to understand it properly and use it reasonably to do better in the prevention and treatment of diseases.