Retinoic acid, generally referred to as retinoic acid, is an intermediate product of vitamin A metabolism in the body. It mainly promotes the proliferation and differentiation of epithelial cells and promotes keratinized cells. Usually retinoic acid is used to treat acne, psoriasis, ichthyosis, etc. The effect of retinoic acid on the skin usually has no effect on normal human melanocytes. However, when the skin undergoes physiological changes or is exposed to drugs, UV radiation and trauma, retinoic acid is effective in correcting or preventing changes in the dermal connective tissue that are harmful, thus protecting the skin. Retinoic acid also has a strong anti-inflammatory effect, as it also has an inhibitory effect on the chemotaxis of leukocytes. It may cause symptoms of skin irritation such as burning sensation, erythema and flaking, which may make the lesions more pronounced. It is recommended to use retinoic acid under the supervision of a doctor and avoid overuse.