The intraoperative use of local anesthetic agents to decrease postoperative pain has been used in many types of procedures. Most of these techniques involve needle injection of anesthetic and result in a low but troublesome incidence of complications. In this study, we evaluated the reliability, safety, and efficacy of a technique emphasizing bathing of tissues with anesthetic rather than needle injection for relieving postoperative pain. Thirty consecutive patients undergoing outpatient elective inguinal herniorrhaphy with general anesthetic were prospectively randomized into four treatment groups. Group 1 received 0.5 per cent bupivacaine plus epinephrine 1 to 200,000; group 2, 0.5 per cent bupivacaine; group 3, normal saline solution, and group 4, no treatment. At the end of the repair, one-third of the test solution (approximately 5 milliliters) was bathed along the spermatic cord throughout its length in the inguinal canal. The external oblique aponeurosis was closed superficial to the cord structures and another one-third of the solution was instilled into the wound. Just prior to the end of skin closure the remaining solution was instilled subcutaneously. No needles were used to instill the solutions and they were not suctioned or removed from the wound. Data collection consisted of an analog type of patient questionnaire allowing subjective assessment of postoperative pain at various time intervals during the first 20 hours postoperatively. Pain medication provided was propoxyphene, 100 milligrams and acetaminophen, 650 milligrams every three hours as needed. Total doses of pain medication for the study period and the time to first pain medication requirement were obtained. Results were analyzed using analysis of variance, and Wilcoxon ranked sums test. Patients in group 1 (0.5 per cent bupivacaine with epinephrine) exhibited significantly less pain than those in groups 3 (saline solution) and 4 (control) for more than 12 hours postoperatively. Patients in group 2 (0.5 per cent bupivacaine) likewise experienced less pain than those in groups 3 and 4 through seven hours. The patients receiving saline solution were not significantly different than those in the control group throughout. Objectively, groups 1 and 2 required fewer total doses of pain medication and waited longer before requesting oral pain medication postoperatively compared with those in the control group. No complications occurred that could be attributed to the technique. The results of this study indicate that the bathing of wounds with 0.5 per cent bupivacaine with or without epinephrine 1:200,000 is a safe and effective method of decreasing postoperative pain for several hours in patients undergoing elective inguinal herniorrhaphy.(ABSTRACT TRUNCATED AT 400 WORDS)