Isolated female rat livers were perfused with a medium containing [14C]LSD (1 mg and 0.13 μCi/g liver) and (+)-tartaric acid (15 mg). After 4.5 hr, the bile collected contained some 44% of the added radioactivity, the perfusate, 20% and the liver itself, 20%. The radioactive compounds in the bile were identified as 14-hydroxy-LSD glucuronide (21% of the added 14C), 13-hydroxy-LSD glucuronide (8%), 2-oxo-LSD (7%) and unchanged LSD (1%). Those in the pooled perfusate and homogenised liver were unchanged LSD (18%), 2-oxo-LSD (5%), a naphthostyril derivative of LSD (4%; probably derived from 2-oxo-LSD), nor-LSD (4%), hydroxy-LSD glucuronides (3%) and de-ethyl-LSD (2%). © 1979.