Polyamine levels were determined by precolumn derivation RH-HPLC in 68 patients with ascites including 21 malignant ascites, 28 liver cirrhosis and 19 tuberculosis. The total polyamine, especially the contents of cadaverine (CA) and spermidine (SPD) in malignant ascites were significantly higher than that in cirrhosis and tuberculosis. Among them CA levels in malignant ascites and cirrhotic and tubercular ascitic fluid were 2.26 +/- 1.83 nmol.ml-1, 0.75 +/- 0.52 nmol.ml-1 and 0.76 +/- 0.47 nmol.ml-1 respectively, demonstrated the most obvious difference. Using 1.0 nmol.ml-1 as a threshold cut off point to differentiate the malignant ascites from non-malignant ascites, the from non-malignant ascites, the sensitivity, specificity and accuracy reached 76. 2%, 83.0% and 80.9% respectively. The results suggest that polymine level in ascites might be regard as one of the cancer-associated markers.