Abstract: THE MEASUREMENT OF TOTAL BODY WATER（TBW）BY GC／MSJiang Ji；Jiao Ying；Li Xiaoming；Hu Yufang；Yang Zeyi；Wang Shizhen（Department of Nuclear Medical College Hospital，Beijing 100730）（Nationd Research Institute of Sports Medicine，Beijing 100029）ABSTRACT Equlibrium speeds of D_2O administered orally in 5 normal adults were measured with the technique of self－chemical ionization on GC／MS．The variations of D_2O in serum，urine and saliva werecompared too．The total body water（TBW）in 6 normal Chinese adults were determined according tothe average dilution in the saliva at 2．5，3 and 3．5 hours after D_2O intake at the dosage of 0．6g／kgbody weight．Key words total body water D_2O GC／MS