Objective To investigate the characteristics of the pharmacodynamics of rocuronium bromide in patients with hepatobiliary disease. Methods Forty-eight patients undergoing abdominal surgery were divided into four groups, group A: patients with liver cirrhosis and portal hypertension (n = 12); group B1 : patients with cholelithiasis and obstructive jaundice (n = 12); group B2 : patients with cholelithiasis but no obstructive jaundice ( n=12);group C: patients without hepatobiliary disease ( n = 12) . Their renal function was normal. Patients with cardiovascular and neurological diseases were excluded. Premedication consisted of intramuscular phenobarbital 0.1 g and scopolamine 0.3 mg. Anesthesia was induced with midazolam 0.05 mg?kg-1 , fentanyl 2?g?kg-1 , propofol 2 mg?kg-1 and rocuronium 0.6 mg?kg-1 . The patients were intubated and mechanically ventilated. PETCO2 was maintained at 30-35 mm Hg. Anesthesia was maintained with iv infusion of propofol and fentanyl. Additional bolus dose of rocuronium 0.15 mg?kg-1 was given when T, recovered to 25% and each patient received six additional doses irrespective of duration of operation. Neuromuscular function was monitored using Datex-Ohmeda NMT mechanosensor. Onset time (from the end of injection to maximum depression of muscle twitch), clinical duration of intubating and additional dose (25 % recovery of T1 ) and recovery index (T1 from 25 % -75 %) were recorded. Results The demographic data were comparable among the four groups. The onset time was significantly longer in group A than that in group B, , B2 and C ( P