The human skin microbiome is closely associated with various diseases. We aimed to find the causal association of the human skin microbiome with vaginitis. A two-way two-sample Mendelian randomization study used summary statistics of the human skin microbiota from the largest genome-wide association study meta-analysis. Pooled statistics for vaginitis disease were obtained from the FinnGen consortium R10 release. Inverse variance weighted, MR-Egger, weighted median, weighted model, MR-PRESSO, and STEIGER methods were used to test for causal associations between different parts of the human ski...