Abstract: m-(2-Dimethylamino) ethoxy phenyl-N, N-dimethyl carbamate (Cui-Xing An) is a new central anticholinesterase drug. After oral administration of Cui-Xing-An to rats, four components were isolated and purified from urine extract by HPLC, They were identified by MS to be the parent drug, m-2-dimethylamino) ethoxy phenyl-N-hydroxymethyl-N-methyl carbamate (hydroxylated Cui-Xing-An), m-(2—dimethylamino) ethoxy phenyl-N-methyl carbamate (N-demethylated Cui-Xing-An) and m-(2-dimethylamino) ethoxy phenol (hydroly sate).Experiment on Torpediniforms Nacline timilei AchE inhibitory rate showed that the N-demethyl Cui-Xing-An had the same anticholinesterase activity as the parent drug. The hydroxylated Cui-Xing-An exhibited lower activity, and the hydrolysate was inactive.