Background Epinephrine infiltration of the nasal mucosa causes hypotension during functional endoscopic sinus surgery (FESS) under general anesthesia. A prospective randomized-controlled study was designed to determine whether relatively light general anesthesia is superior to fluid expansion in reducing epinephrine-induced hypotension during FESS.Methods Ninety patients undergoing elective FESS under general anesthesia were randomly assigned to three groups with 30 patients in each. Each patient received local infiltration with adrenaline-containing (5 μg/ml) lidocaine (1%,4 ml) under different conditions. For Group Ⅰ, anesthesia was maintained with propofol 2 μg/ml and rimifentanil 2 ng/ml by TCI. Group Ⅱ (control group) and Group Ⅲ received propofol 4 μg/ml and rimifentanil 4 ng/ml, respectively. In Groups Ⅰ and Ⅱ, fluid expansion was performed with hetastarch 5 mi/kg within 20 minutes; hetastarch 10 ml/kg was used in Group Ⅲ. Mean arterial pressure (MAP) and heart rate (HR) were recorded at 30-second-intervals for 5 minutes after the beginning of local infiltration. Simultaneously, the lowest and the highest MAP were recorded to calculate the mean maximum increase or decrease percent in MAP for all patients in each group. Data analysis was performed by χ2 test,one-way analysis of variance, or one-way analysis of covariance.Results Hemodynamic changes, particularly a decrease in MAP accompanied by an increase in HR at 1.5 minutes(P＜0.05), were observed in all groups. The mean maximum decrease in MAP below baseline was 14% in Group Ⅰ, 24% in Group Ⅲ and 26% in Group Ⅱ. There were statistically significant differences between Group Ⅰ and Groups Ⅱ and Ⅲ(P＜0.05). The mean maximum increase in MAP above baseline was 9% in Group Ⅰ, 6% in Group Ⅲ and 2% in Group Ⅱ.Conclusion Relatively light general anesthesia can reduce the severity of epinephrine-induced hypotension more effectively than fluid expansion during FESS under general anesthesia.