Plasma noradrenaline (NA) and adrenaline (A) concentrations were related to various haemodynamic parameters in fifteen patients with cirrhosis. In supine position at rest plasma NA and A in peripheral venous blood were significantly higher in patients with cirrhosis than in normal subjects. Mean plasma NA averaged 0.66 and 0.21 ng/ml, respectively (P less than 0.01). The corresponding values for plasma A were 0.14 and 0.05 ng/ml (P less than 0.03). Splanchnic arterial-hepatic venous extraction ratio of NA in patients with cirrhosis averaged 0.46 (P less than 0.01). The right kidney released NA into the systemic circulation. Renal venous plasma NA exceeded arterial concentration by 38% (P less than 0.02). NA concentrations in femoral vein and ascitic fluid were not different from that of arterial plasma. Plasma NA was positively correlated to wedged hepatic vein pressure (r = 0.86, P less than 0.001) and to heart rate (r = 0.61, P less than 0.02), but inversely correlated to plasma volume (r = 0.83, P less than 0.01) in cirrhotic patients. Arterial blood pressure was reduced in these patients compared to controls (P less than 0.02), but not significantly correlated to plasma NA. The increased plasma NA indicates that sympathetic nervous activity is enhanced in patients with cirrhosis. Based on the above positive correlation between NA and heart rate and the significant release of NA from the kidney, it may be hypothesized that the increased sympathetic nervous activity especially involves heart and kidney. This response may be mediated by baro- and volume receptors.