Abstract: Tetramethylpyrazine(TMP), an active principle isolated from the traditional Chinese herb, Ligusticum Wallichii Franch,has been widely used in the treatment of patients with cerebral ischemic diseases in China, In order to investigate its metabolism, we synthesized deuterium-labeled TMP from deuterated butanone which was obtained by the exchange of butanone with deuterium oxide in the presence of potassium carbonate. The resulting deuterium-labeled TMP exhibited characteristic isotopic clus ters in its CI mass spectrum and its average deuterium content was 3.3 D/mole.