The chart is based on research from two doctors, Stephen Lewis and Ken Heaton, at Bristol Royal Infirmary in the UK. In one key study, published in 1997, they had 66 adult volunteers keep diaries about how their poop looked and how often they went. Participants also swallowed marker pellets...
Stool consist- ency was determined by each subject using the Bristol Stool Chart, which has a 7-point scale from Type 1 for the hardest lumpy stools representing constipation to Type 7 for the watery stools representing diarrhoea. Ideal stool consistency covers scores from 3 to 4. Stool volume...
Southwell BR, Clarke MCC, Sutcliffe J, Hutson JM (2009) Colonic transit studies: normal values for adults and children with comparison of radiological and scintigraphic methods. Pediatr Surg Int 25:559–572. doi:10.1007/s00383-009-2387-x Article Google Scholar Lampe JW, Fredstrom SB, Slavin...