The absorption, distribution, excretion and metabolism of 14C labelled 2-chlorophenyl-1-phenyl-3-(2 methyl-piperidino) propyl ether methyl iodide (14C-R97) were studied by means of direct measurement of radioactivity and autoradiographic technique in rats. 1) With intravenous administration, radioactivity was found in all the tissues and organs immediately after dosing, with particularly high levels in the liver, kidney, heart and lung. Five minutes after administration, the level of radioactivity in blood decreased to about 6% of the initial level, indicating the rapid absorption of radioactive material by other tissues and organs. Radioactivity was not detected in the brain and eye. Thirty minutes after administration, the concentration of radioactivity in the gastrointestinal contents was very high and a certain amount of radioactivity uptake was noted both in gastric and intestinal mucosa. Approximately 12% and 40% of radioactivity administered was excreted in the urine and feces respectively during the first 24 hours, however, the excretion of radioactivity by expiration was not determined. 2) With oral administration, radioactivity was restricted to the gastrointestinal tract. Activities in other tissues and organs were not detectable. Approximately 94% of the radioactivity administered was recovered in feces during the first 24 hours. 3) Radioactivity was not observed in either the foetus or placenta after both intravenous and oral administrations. 4) The results from autoradiographic study were in good accord with those described above.