Vitamin A Acid Ointment works by promoting epidermal cell renewal and regulating epidermal cell differentiation and proliferation; it works to treat conditions such as acne vulgaris and solar lentigines. The efficacy of retinoid ointment is to promote the renewal of epidermal cells, regulate the differentiation and proliferation of epidermal cells, so that the cells of the stratum corneum can be easily exfoliated, removing acne, and also inhibit the formation of new acne. It can be used to treat common acne, such as blackheads and pimples lesions, as well as for senile, drug-induced or sunlight-induced skin atrophy, and keratosis pilaris. Patients should avoid sun exposure while using the medication to avoid aggravating the skin irritation caused by retinoids. Adverse reactions such as erythema, flaking, crusting, and swelling may occur with the use of retinoic acid ointment; these adverse reactions, if they persist, should be discontinued immediately and a visit to the hospital should be made. Precautions: This product should be kept away from the eyes, should not be used on skin folds, most preferably applied at night and before bedtime, and should not be applied over a large area. The use of retinoic acid ointment is prohibited for those who are allergic to the drug, patients with acute or subacute dermatitis, eczema-type skin diseases, and women in the third trimester of pregnancy. If you need to use retinoic acid ointment, it should be used under the guidance of a doctor, and should not be used privately, so as to avoid adverse effects and delay the condition.