Objective To investigate the effect of adriamycin on gut fungi in SD rats.Methods Fourteen SD rats were randomly divided into control and adriamycin groups,rats in adriamycin group were administered with adriamycin 7.5 mg/kg by single tail vein injection.The rat feces were collected for ITS2 sequencing and bioinformatics analysis after 6 weeks.The gut fungal abundance and diversity were compared between two groups and the differential genera were identified.Results ITS2 sequencing results showed that there were no significant differences in abundance and diversity of gut fungi between adriamycin group and control group(P>0.05),while Beta diversity varied significantly(P<0.05).The composition of gut fungi:at the phylum level Ascomycota,unclassified-Fungi,unclassified,Basidiomycota,Chytridiomycota and Glomeromycota were predominant;at the family level Erysiphaceae,unclassified-Fungi,unclassified,Sporidiobolaceae,and Aspergillaceae were predominant;at the genus level,the relative abundance from high to low was Erysiphe,unclassified-Fungi,unclassified,Cladosporium,Aspergillus,etc.The LEfSe results revealed that the relative abundance of 13 fungi including unclassified-Fungi,Byssochlamys,Alternaria,Chrysosporium decreased significantly at the genus level after adriamycin treatment,while the relative abundance of Trichoderma,Cryptococcus,Actinomucor,and Blumeria increased significantly.Conclusion The diversity of rat gut fungi is changed significantly after adriamycin treatment and the abundance of certain gut fungi is changed at different taxonomic levels.