A clinical comparison of 28 patients was done in a double-blind fashion to evaluate the effectiveness of 1.5 etidocaine with epinephrine 1:200,000 and 2% lidocaine with epinephrine 1:100,000 in oral surgery. The patients selected had no medical problems, but required the extraction of bilaterally impacted third molars. Each subject served as his or her own control with etidocaine being used to produce local anesthesia on one side of the face, and lidocaine on the opposite side. The results were evaluated to allow a comparison of the onset and quality of anesthesia; the duration of lip numbness and the onset of postoperative pain; and the incidence, type, and severity of adverse reactions. Both lidocaine and etidocaine were similar in onset and quality of anesthesia. No adverse reactions were observed with either agent. The two anesthetics differed mainly in their durations of action. Etidocaine proved 2.16 times longer acting than lidocaine with respect to recovery from lower lip numbness and 1.75 times longer acting than lidocaine with respect to the onset of postoperative pain. Therefore, the conclusion was reached that 1.5% etidocaine with epinephrine 1:200,000 is an effective local anesthetic for use in oral surgery because it has a rapid onset, provides profound anesthesia, and possesses a longer duration of action than 2% lidocaine with epinephrine 1:100,000. The final characteristic is of particular value as the onset of postoperative pain is significantly delayed.