Adapalene gel is hormone-free and its main ingredient is adapalene, a retinoid compound. Its chemical composition is Adapalene, 6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphthoic acid molecular formula C28H28O3. Adapalene has a strong anti-inflammatory effect in addition to the role of retinoic acid drugs can dissolve acne, has the role of inhibiting sebum secretion and promote epidermal metabolism, clinical mainly used for the treatment of acne vulgaris, pimples, pustules-based acne. However, Adapalene may be irritating when applied topically, and some patients may experience skin redness, swelling, molting, and burning sensation during the initial or extensive use. In such cases, it is necessary to reduce the dosage or apply it to a small area or spot on the acne as prescribed by the doctor and wait until it is tolerated before gradually recovering, and apply topical moisturizers or ice packs as appropriate. However, if allergy or severe irritation occurs, the medication should be stopped. It should also be noted that adapalene is contraindicated in the eyes, mouth, nasal mucosa and other mucosal tissues. If it accidentally stains or enters these mucosal tissues, it should be washed off immediately with warm water. Adapalene is also contraindicated in broken skin (cuts, abrasions, etc., and in severe acne, if there are broken lesions), and eczema-like skin wounds. Adapalene is not recommended for use during pregnancy because there are no studies on its use in pregnant women. Also, because it is not known whether adapalene is secreted in breast milk, use with caution in breastfeeding women and do not apply to the chest if it is necessary to use this product.