AbstractPopulation samples from 4 study areas showing a 3‐fold variation in large bowel cancer incidence were investigated for fecal bile acid loss and concentration, fecal neutral steroid loss and concentration, and urinary loss of volatile phenols.. Each sample consisted of 30 randomly selected men, aged 50–59 years.Daily loss of bile acids was found to be identical in the 4 areas, but due to differences in fecal bulk, the fecal bile acid concentration varied, showing a positive correlation with large bowel cancer incidence. No significant difference between the 4 populations emerged with regard to fecal neutral steroids or urinary volatile phenols.