Abstract: Yan Huimin, Zhao Huijuan, Guo Duyi, Zhang Chunlei, Jiang Wei Department of Dermatology, Peking University Third Hospital, Beijing 100191, China Corresponding author: Jiang Wei, Email: jiangwei7366@163.com 【Abstract】 Objective To compare differences of gut microbiome between patients with severe acne vulgaris and healthy individuals by using high?throughput sequencing technology. Methods Stool samples were collected from 10 outpatients with severe acne vulgaris and 10 age? and sex?matched healthy controls. Then, the bacterial DNA was extracted and subjected to 16S rRNA sequencing for the identification of microbial species, and the differences of gut microbiome were compared between the patients and controls. Results There were no significant differences in the diversity of intestinal microflora, but only the relative abundance of a few bacteria differed significantly between the two groups. Gut microbiome in the two groups mainly consisted of Bacteroidetes, Firmicutes, Proteobacteria and Actinobacteria. There were no significant differences in the relative abundance of bacteria at the phylum and genus levels between the two groups. However, the relative abundance of Blautia producta and Coprococcus eutactus at the species level differed remarkably between the two groups. Conclusion No significant differences in the bacterial diversity indices are found, but some bacterial species significantly differ between the patients with severe acne vulgaris and healthy controls.