A method was developed to measure the tetramine in plasma by liquid-liquid extraction and GC-NPD with the limit of detection (LOD) 1.5 pg and the limit of quantity 10 ng/ml. The linear range was 0.1-5 micrograms/ml with a correlation coefficient of 0.999. Recoveries for three concentrations of tetramine were 96.0%, 107.0%, 106.8%. The intra-day precision were 9.6%, 9.8%, 7.8%, the inter-day precision were 6.6%, 8.5%, 6.2%. Tetramine in plasma was stable up to 5 months at -4 degrees C.