YM155 monobromide is a novel small-molecule survivin suppressant. The pharmacokinetics, distribution and excretion of YM155/[14C]YM155 were investigated using males and pregnant or lactating female rats after a single intravenous bolus administration. For the 0.1, 0.3 and 1 mg/kg YM155 doses given to male rats, increases in area under the plasma concentration–time curves were approximately proportional to the increase in the dose level. After administering [14C]YM155, radioactivity concentrations in the kidney and liver were highest among the tissues in both male and pregnant rats: e.g. 14.8- and 5.24-fold, respectively, and higher than in plasma at 0.1 h after dosing to male rats. The YM155 concentrations in the brain were lowest: 25-fold lower than in plasma. The transfer of radioactivity into fetuses was low (about 2-fold lower than in plasma). In lactating rats, the radioactivity was transferred into milk at a level 8- to 21-fold higher than for plasma. Radioactivity was primarily excreted in feces (64.0%) and urine (35.2%). The fecal excretion was considered to have occurred mainly by biliary excretion and partly by secretion across the gastrointestinal membrane from the blood to the lumen. Copyright © 2012 John Wiley & Sons, Ltd.