The excretion, distribution and metabolism of3H-phencyclidine (PCP) were studied in male rats following oral administration. The radioactivity was mainly excreted in urine and to a lesser extent in feces. Most of the urinary radioactivity was excreted in the form of glucuronide conjugates of hydroxylated PCP metabolites and urinary excretion of unchanged PCP was minimal. Distribution study showed no marked amity for any particular tissue, although the levels in liver and prostate were a little high within 24 h after dosing. PCP was detected in brain by GC-MS.