After i.v. injections of cocaine, norcocaine, pseudococaine to the rat, the T 1/2 in brain were 0.4, 0.6, 0.2 h respectively and in plasma 0.4, 0.5, 0.2 h respectively. Benzoylnorecgonine and norecgonine were the metabolites of norcocaine in brain. Pseudonorcocaine, pseudobenzoylnorecgonine, pseudobenzoylecgonine and pseudoecgonine were the metabolites of pseudococaine in rat brain. Benzolynorecgonine and pseudobenzoylecgonine had potent stimulant activity intracisternally in the rats.