Administration of antibiotics and topical retinoic acid can have synergistic effects through their different pathways of action, and the combination of these two approaches can clear lesions faster for inflammatory damage and acne than antibiotics alone. Also topical retinoic acid can shorten the duration of antibiotic treatment, increase antibiotic penetration and increase follicular cell turnover, thus allowing more antibiotics to reach the sebaceous units and reducing the incidence of drug resistance. Combination therapy is currently the standard of care for mild to moderate acne. Advantages of combination therapy: 1. Clinical efficacy of antibiotics and topical retinoic acid is significantly better than antibiotics alone; 2. Faster onset of action on inflammatory damage and acne; 3. Combination of peroxybenzoyl or topical retinoic acid with oral antibiotics reduces the incidence of drug resistance; 4. Combination of topical peroxybenzoyl should be used when prolonged antibiotic use is required. 5, the combination of topical retinoic acid and benzoyl peroxide can be used daily with one or both drugs alternately in the morning and evening.