The pathogenesis of salt and water retention in cirrhosis remains unclear. Systemic and portal hemodynamic parameters, including cardiac output, portal pressure gradient and systemic vascular resistance, were measured in six patients with untreated ascites and in six patients with hepatic cirrhosis with no history of ascites. Renal blood flow, urinary volume, and humoral factors, including plasma renin, aldosterone, angiotensin II, and urine kallikrein, were measured. Significant differences were seen between the two groups in urine volume, urine sodium and fractional sodium excretion, plasma angiotensin II, and the ratio between plasma renin activity and urinary kallikrein excretion (PRA:UKallV). A strong correlation existed between urinary sodium excretion and the PRA:UKallV ratio. No significant differences were detected between the groups in portal, renal, and systemic hemodynamics. The present results suggest that humoral changes occur early in ascites. Altered relationships between intrarenal hormone systems, such as the renin-angiotensin and kallikrein-kinin systems, may be important in salt and water retention.