Vitamin A cream is used by gently applying the medication to the affected area, the specific frequency of use is related to the disease, usually choose to use before bedtime. Vitamin A cream in the treatment of acne, generally choose to use once a night before going to bed can be; in the treatment of ichthyosis, psoriasis, you can increase the number of times a day to 2 ~ 3 times, should pay attention to avoid light. After the drug is applied, it should be gently rubbed to promote the absorption of the drug. Vitamin A cream should not be used over a large area, and the total amount used per day should not exceed 20 grams. Adverse effects of retinoic acid cream are mainly local erythema, burning and flaking, etc., which can be tolerated and gradually adapted to, and do not need to stop treatment. It should be contraindicated in skin folds, eyes and areas with severe oozing. If irritation persists and worsens after use, discontinuation or intermittent use should be given under medical supervision.