“…Bacterial deconjugation of bile acids occurs in the small intestinal lumen of animals with surgically created blind loops (Donaldson, 1965;Kim et al, 1966) and of patients Departments of Medicine and Biochemistry, Guy's Hospital, London SEI 9RT T. C. NORTHFIELD, M.D., M.R.C.P., Senior Registrar with the stagnant loop syndrome (Donaldson, 1965;Tabaqchali and Booth, 1966). Free (unconjugated) bile acids inhibit the uptake and esterification of fatty acids by small intestinal slices in vitro (Dawson and Isselbacher, 1960), but this does not appear to be the mechanism of fat malabsorption in vivo (Gallagher et al, 1968;Cheney et al, 1970;Clark et al, 1970).…”