L-carnitine (L-C) is a naturally occurring substance in mammalian tissues that has recently been proposed as a therapeutic agent in hepatic encephalopathy and liver steatosis. L-C also produces some acute, non-metabolic, haemodynamic effects that have not previously been studied in patients with cirrhosis. Therefore, the authors evaluated the acute effect of i.v. administration of L-C (30 mg/kg) on systemic and splanchnic haemodynamics in ten patients (L-C group) with chronic liver disease (Child-Pugh's class A: 4, B: 3, C: 3 patients) and a control group composed of ten patients with similar clinical characteristics (Child-Pugh's class A: 5, B: 2, C: 3 patients) who received placebo. Heart rate, cardiac index and pulmonary arterial pressure (measured by right heart catheterization) decreased slightly but significantly in the L-C group and the changes observed in stroke volume were highly correlated to the Pugh's score. Moreover, the hepatic venous pressure gradient (measured by hepatic vein catheterization) decreased significantly in the L-C group, whereas no changes occurred in the placebo group. The overall response to L-C was contradictory to that previously observed in animals and humans with normal liver function, and the extent seemed to depend on the severity of liver disease. The effect of the drug on cardiac index, heart rate and hepatic venous gradient could possibly be beneficial for patients with hyperdynamic circulatory condition and portal hypertension.