Abstract: The analysis of human urine metabolites of norethisterone by GC-MSis presented.After a healthy female had orally taken 40 mg of norethisterone, her urine samples were collected and stored.Two main metabolites of norethisterone (Met 1, Met 2) were identified in the urine sample 5 h after taking norethisterone.According to previous research.there were two other metabolites of norethisterone (Met 3, Met 4)which were the same as those of nandrolone and thus would disturb the detection of the banned nandrolone in doping control test.However, our investigation shows that normally, the excretion concentration of Met 3 and Met 4 in human body are very low after the administration of norethisterone, which is easily distinguished from the case of administration of banned nandrolone in examination of athletes’ urine.

Key words: Norethisterone, Nandrolone, Metabolites, GC-MS analysis