The Baker-Gordon phenol-croton oil peel has been the standard deep chemical peeling formula for many years. In 2000, Hetter published several articles demonstrating the clinical effects of various dilutions of the Baker-Gordon formula. He suggested that croton oil concentration was more important than phenol concentration in obtaining desired depth of injury and minimizing complications. This study sought to better define the effect and interaction of phenol and croton oil. Various concentrations of these agents were applied to tattooed grids on the bilateral flanks of a 4 month-old Yucatan pig. Dilutions of phenol, (50%, 27%, 0%) mixed with varying concentrations of croton oil, (2.2%, 1.6%, .9%, .5% , .1% , and 0%) were studied. Three carriers were also studied-water, ethanol, and glycerine. Punch biopsies were taken at day 0, 2, 4, 9, 18, and 120 days after peeling. H&E staining was used to evaluate peel depth, re-epithelialization, new collagen, and melanocyte activity. Clinical photographs were correlated with the histology. Results will be presented Croton oil and phenol alone are not effective peeling agents. Small concentrations of croton oil are able to potentiate the peeling effects of phenol. Water and ethanol allow this potentiation, but glycerine prevents the effect.