The effects of varying rates of alcohol infusion (0.015-0.12 mg/g body weight/min) on hepatic haemodynamics were studied in male Wistar rats. An infusion of 0.015 mg/g body weight/min alcohol had no significant effect on portal pressure (PP) or wedged hepatic venous pressure (WHVP). However, increasing rates of infusion of alcohol (0.03-0.12 mg/g body weight/min) progressively increased PP and WHVP, the maximum increase in PP occurring following an infusion of 0.12 mg/g body weight/min (6.5 +/- 0.5 - 10.3 +/- 0.6 mm Hg). The effect of varying rates of alcohol infusion on portal venous flow and liver blood flow was biphasic. Thus following an infusion of 0.03 mg/g body weight/min alcohol, liver blood flow (40.6 +/- 4.9 - 54.3 +/- 5.8 ml/100 g/min) and portal venous flow (28.6 +/- 2.9 - 41.3 +/- 4.1 ml/min) were increased. However, following infusions of 0.06 and 0.12 mg/g body weight/min alcohol, liver blood flow and portal venous flow were decreased. The results suggest that previous conflicting reports on the effects of alcohol on hepatic haemodynamics may be related to the dose of alcohol administered.