Large-volume paracentesis with a plasma expander has been extensively evaluated and shown to be an effective and safe therapy. While hepatic and systemic hemodynamics have been studied extensively, there is little information on portal hemodynamics by duplex Doppler. Portal vein diameter, portal flow velocity, and portal blood flow were measured with duplex Doppler in 11 cirrhotic patients before and 24 hr after large volume paracentesis. There were no significant changes in the portal vein diameter (9.88 ± 2.62 mm vs 10.09 ± 2.73 mm), portal flow velocity (10.65 ± 2.60 vs 10.01 ± 2.58 cm/sec), and portal blood flow (488 ± 288.9 vs 502 ± 273.38 ml/min), before and 24 hr after large-volume paracentesis. Thus, significant changes in portal hemodynamics do not occur after large-volume paracentesis.