Side effects, i.e. adverse reactions, are commonly known as mometasone furoate gel for 999 dermatitis. Adverse reactions such as burning sensation and hirsutism may occur, but are generally harmless. As this drug is a glucocorticoid, long-term use can cause irritation reactions, skin atrophy, hirsutism, perioral dermatitis, secondary infections, hyperpigmentation and other adverse reactions. Its adverse reactions are mild and usually disappear on their own after stopping the drug. Mometasone furoate gel is used for eczema, neurodermatitis, atopic dermatitis and pruritus, with anti-inflammatory, anti-allergic, anti-itching and reduce oozing effect. It needs to be contraindicated in patients who are allergic to any of the components of the product. Patients are advised to use mometasone furoate gel under medical supervision and not to self-medicate to avoid adverse reactions.