Two anesthetic procedures, intercostal nerve block (ICNB) and general anesthesia, were evaluated in 45 female patients scheduled for minor breast surgery. The study was designed to compare ICNB with general anesthesia for breast surgery with respect to efficacy, surgical stress and postoperative analgesia and to evaluate epinephrine and ornipressin as vasoconstrictors in the local anesthetic solution. Thirty patients received ICNB of T3-T7 unilaterally using 2% lidocaine plus epinephrine (15 patients, Group A) and 2% lidocaine plus ornipressin (15 patients, Group B). The control group consisted of 15 patients receiving a general anesthetic. The highest median lidocaine plasma level was 2.8 micrograms/ml in those patients who received epinephrine and 5.3 micrograms/ml in those who received ornipressin. There were statistically significantly higher lidocaine plasma levels in Group B than in Group A after 10, 30 and 60 minutes from injection while the two groups did not differ significantly at the 20- and 90-minute time intervals. Before and during surgery, epinephrine and norepinephrine plasma levels were highest in the epinephrine group, whereas, postoperatively, the plasma levels of both catecholamines were highest in the patients receiving general anesthesia. The latter patients experienced significantly more nausea and vomiting than the regional anesthesia groups. Patients with regional anesthesia required significantly less analgesics postoperatively than the patients receiving general anesthesia.