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We have observed 5 patients with hypertrophic scarring at the lateral boundaries of the chemically peeled area when circumoral peel was combined with facial rhytidectomy. Some of the potential contributory factors include flap elevation, epinephrine, and lidocaine hydrochloride. To discover whether any one of these three factors or a combination played a role, a rat model study was designed. Initially, 40, 400-gm Sprague-Dawley rats were divided into 4 groups, each comprised by 10 rats. Injections with lidocaine or lidocaine with epinephrine, and chemical peel were done in 2 groups. The same injections were used in the remaining 2 groups together with simultaneous preliminary flap elevations and chemical peeling. After the review of the initial study results, another 40 Sprague-Dawley rats were used to repeat the study and compare on a larger scale the effects of lidocaine with and without epinephrine on the depth of chemical peel. The findings of the rat model studies indicate that preliminary injections with lidocaine containing solution (with or without epinephrine) result in a major delay in healing time. Flap elevation and chemical peeling were associated with major morbidity and mortality in the test rats. The presence of epinephrine in lidocaine solution had no significant role in increasing the delay in the healing process.