Fusidic acid and erythromycin ointment both belong to the antibiotic class of topical medications, but there is a difference between them. There is no such thing as which one works, and its effect varies from person to person and from condition to condition. 1. The two components are different: the main component of fusidic acid is fusidic acid, while erythromycin ointment is erythromycin as the main component. 2. The indications are different: fusidic acid is mainly used for skin infections caused by gram-positive cocci. For example, pustulosis, boils, folliculitis, sweating inflammation, onychomycosis, common acne, eczema co-infection, trauma co-infection, ulcer co-infection and so on. Erythromycin ointment can be used for purulent skin diseases such as impetigo, infections of ulcers and small burns. Adverse effects of fusidic acid are mainly irritation, and it is contraindicated for those who are allergic to its ingredients. Adverse reactions to erythromycin ointment are irritation and allergic reactions, and it is contraindicated for those who are allergic to this product. Both drugs should be used under the supervision of a clinician.