The localization, distribution, elimination and metabolism of 14C-Sulpiride administered in doses of 20 mg/kg by i. p. and oral route in rats is described. Whole-body autoradiography and quantification in organs and tissues as a function of time showed that the distribution of radioactivity throughout the body is general with the highest level in the kidineys, pelvis, liver and hypophysis I hour after administration. The blood radioactivity level reaches its maximum 5 minutes after i. p. administration with a value of II Jlg/ml, of which 85 % is due to unchanged Sulpiride. At later determinations, the amount drops to 60-65 % of unchanged Sulpiride. In the bile, the maximum radioactivity is measured between I and I hour 1/2 in either extra-corporal circuit or choledocal fistula. After i. p. administration, urinary elimination is an average of 64 %of the administered dose in 72 hours, of which 70 %to 55 %, depending on the period, is due to unchanged Sulpiride. Fecal elimination after i. p. administration is an average of 26 % of the administered dose in the 72 hours period. Conversely, after oral administration, urinary elimination represents an average of 18 % of the administered dose in 72 hours and fecal elimination represents an average of 74 %for the same period. Aside from the unchanged product, 7 to 8 metabolites were separated and quantified at the plasmatic, urinary and biliary level. Very low amounts of radioactivity were recovered as "CO. indicating that the labelled position is very stable.