Recent studies in the area of the phenol-croton oil chemical peels have raised questions regarding many long-standing dogmas of phenol peels. One recent clinical study concludes that it is the croton oil, and not the phenol, that produced the most profound effect on the depth of peel. Using a porcine model, we attempted to examine the validity of this conclusion by histologically evaluating the depth of injury following phenol-croton oil peels. Three groups were investigated: 1.) varying concentrations of phenol without croton oil. 2.) varying concentrations of phenol with a constant amount of croton oil & 3.) a constant amount of phenol with varying amounts of croton oil. Biopsies were taken on day 3, 10, and 28 and assessed histologically for inflammation, fibrosis, and depth of injury. We find that increasing concentrations of phenol increases depths of injury. With a constant amount of croton oil and increasing amounts of phenol, there is an increase depth of injury, which is greater than that with phenol alone. Croton oil; therefore, acts synergistically with phenol to increase the depth of injury. With a constant amount of phenol and increasing amounts of croton oil, effects on inflammation, fibrosis, and depth of injury are minimal.