To explore the clinical effect of isotretinoin in the treatment of moderate acne vulgaris. Methods A total of 80 patients with moderate acne vulgaris admitted to Linwei District Hospital of Traditional Chinese Medicine of Weinan City from August 2019 to August 2020 were selected as the research objects. According to the different treatment schemes used by the patients, they were divided into reference group and observation group, with 40 patients in each group. The reference group was treated with tazarotene cream, and the observation group was treated with isotretinoin erythromycin gel. The skin lesions, clinical efficacy and adverse reactions of the two groups after treatment were compared. Results After treatment, the skin lesions in the observation group were better than those in the reference group (P <0.05). The total effective rate of clinical treatment in the observation group was 97.50%, which was higher than 80.00% in the reference group (P <0.05). The incidence of adverse reactions in the observation group was 0, which was lower than 12.50% in the reference group (P <0.05). Conclusion Isotretinoin can improve the skin lesions of patients, improve the total effective rate of clinical treatment, and reduce the occurrence of adverse reactions.