2-[Bicyclo(2,2,1)heptane-2-endo-3-endo-dicarboximido]-glutarimide (taglutimide, K-2004) proved to be a new sedative-hypnotic drug which did not produce any toxic effects when administered orally to mice even at a very high dosage. Central-nervous depression was demonstrated by a reduction in spontaneous motor activity, potentiation of the central-depressant effect of pentobarbital, antagonism of the central-stimulant effect of amphetamine after oral administration and by narcotic activity after i.v. administration of the drug. Furthermore, oral administration of taglutimide potentiated the analgesic action of morphine without being effective on its own. Only weak potentiation of chlorpromazine-induced catalepsy, but not of reserpine-induced catalepsy was observed after taglutimide pretreatment. The drug influenced neither motor co-ordination nor the toxicity of ethanol. Taglutimide exhibited no anticonvulsant activity with respect to maximum electroshock or strychnine-induced seizures. No effect on heart rate or blood pressure was demonstrable after taglutimide treatment in conscious dogs.