Strain GAM6-1T is a novel, strictly anaerobic, non-spore-forming, Gram-stain-positive bacterium that was isolated from the faeces of a healthy individual. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain GAM6-1T was most closely related to Blautia producta ATCC 27340T (95.7 % sequence similarity), in the family Lachnospiraceae. Strain GAM6-1T did not exhibit catalase or oxidase activity. The strain's cellular fatty acids were of the straight-chain saturated and mono-unsaturated types, with C14:0 (24.10 %), C16:0 (19.09 %) and C16:0 dimethylacetal (14.35 %) predominant. Strain GAM6-1T was able to produce acid from various carbohydrates. Glucose fermentation produced acetic acid as the major short-chain fatty acid. The genomic DNA G+C content of strain GAM6-1T was 35.6 mol%. Based on phenotypic, genotypic and phylogenetic evidence, strain GAM6-1T (=KCTC 5981T=JCM 17204T) is considered to represent a novel species, for which the name Blautia stercoris sp. nov. is proposed.