Both azelaic acid and adapalene gel can be used in the treatment of mild to moderate acne, as they both have the effect of dissolving microcomedones and regulating follicle keratinization, so they generally do not have to be used together, if they have to be used together, azelaic acid can be used in the morning, and adapalene gel can be used in the evening. In the morning, use mild cleansing products to clean the face, lightly coated with a layer of azelaic acid, fully massaged until absorbed, because it belongs to the acid products, so there is a certain degree of irritation to the skin, which can lead to skin erythema, desquamation, so it should be gradually build up tolerance, and gradually prolong the duration of the drug stay face. Because adapalene gel has photosensitivity, so the drug should be avoided after sun exposure, generally used at night, this product is the same as azelaic acid, can lead to skin burning, flaking, so the same should be gradually build up tolerance, gradually extend the time of use of the drug, if the face is uncomfortable, you should use water in time to wash away the drug. It is recommended that the drug be used under the guidance of a physician or pharmacist.