Acne is a chronic inflammatory lesion of the sebaceous glands of the hair follicles, characterized by acne, papules, pustules, nodules, cysts and scars, often involving the face, back and chest, where sebaceous glands are abundant. The etiology and pathogenesis of acne are complex, with four main factors: androgens, increased sebaceous secretion, abnormal hyperkeratosis at the opening of the sebaceous glands of the hair follicles, and infection by Propionibacterium acnes. Treatment of acne: The aim is to address several factors in the pathogenesis of acne, namely, inhibition of abnormal keratinization of the follicular sebaceous glands, anti-androgen and sebum hypersecretion, and anti-acne propionibacterium. Avoid alcohol and spicy foods. Wash your face with warm water and neutral soap to remove grease, avoid squeezing the skin lesions, and take oral medications, such as retinoic acid 0.5~1mg/kg/d in two doses for about 16 weeks. For severe nodules, cysts or scarring acne, side effects mainly include dry skin and teratogenicity. It is prohibited in the first 4 weeks of pregnancy. Topical medications: 0.025%, 0.05% or 0.1% retinoic acid emulsion can be used for acne lesions. retinoic acid is irritating to the skin and should be applied once a day at night starting from a low concentration to avoid increased irritation after light exposure. 0.1% adapalene (high name Daphne) is also effective and should be used once a day at night. Benzoyl peroxide preparations can be formulated into 2.5%, 5% and 10% different concentrations of lotions, emulsions or gels, starting from low concentrations, the current market application of Bansai is such products.