The effect of epinephrine on epidural biock and blood lidocaine concentration was investigated in women undergoing elective cesarean sections (n=24). Patients were randomly allocated to one of the two groups; one group received 2% lidocaine 20ml plain (group l, n=12), the other group received 2% lidocaine mixed with epinephrine 1 in 200,000 (group 2, n=12). Matemal venous blood samples were obtained 10, 20, 30, 45, 60 and 90 minutes following the injection. The mean blood concentration of lidocaine in group 2 was significantly lower than that of group 1, 20 minutes following the injection (P<0.05). The addition of epinephrine to the lidocaine solution reduced the peak blood concentration by 24% (from 3.93 to 3.01 ug/ml); however, this did not prolong the times at which the peak concentration was reached. The group 1 (plain) needed significantly more supplementary analgesia than group 2. The time from injection to Bromage scale 0 of group 2 (88.2+/-21.3 minutes) was significantly longer than that of group 1 (52.8+/-10.0 minutes). Incidence of matemal hypotension during operation, nausea/vomiting and shivering in the recovery, room did not differ significantly between the two groups. From this we came to the conclusion that epidural epinephrine reduces blood concentration of lidocaine and improves the duration and the quality of epidural anesthesia during cesarean sections.