Coprococcus (ATCC 27759) is a genus of anaerobic cocci which are all part of the human faecal flora, but rarely seen in human clinical specimens. 'Coprococcus includes those gram-positive, anaerobic cocci that actively ferment carbohydrates, producing butyric and acetic acids with formic or propionic and/or lactic acids. Fermentable carbohydrates are either required or are highly stimulatory for growth and continued subculture.' - Lillian V. Holdeman & W. E. C. Moore. The genus is bio-chemically closely related to Ruminococcus, and phylogenetically to the genus Lachnospira. Coprococcus eutactus is an obligately anaerobic, nonmotile, gram-positive coccus occurring in pairs or chains of pairs. Cells may lose colour readily and acquire a slightly elongate shape in a medium containing a fermentable carbohydrate, but are normally round, and 0.7 to 1.3 µm in diameter. Coprococcus may be used as a microbial biomarker to assess the health of the human gastro-intestinal tract. Gut microorganisms maintain gastro-intestinal health and the mounting evidence of gastro-intestinal problems in autistic children makes a link between autism and intestinal microbiota highly probable, but the paucity of data on intestinal microflora means a definite link has not yet been demonstrated. Early studies overlooked potentially beneficial gut flora missing in autistic children. 'kopros' - excrement, faeces; 'kokkos' - berry; 'Coprococcus' - faecal coccus 'eutaktos' - orderly, well-disciplined (referring to the uniform reactions of the different strains)