Once considered the standard for deep facial resurfacing, the classical Baker-Gordon phenol-croton oil peel has largely been replaced by formulas with lower concentrations of phenol and croton oil. The improved safety profile of deep peels has ushered in a new era in chemical peeling. Wrinkles can be improved and skin can be tightened with more subtle and natural results. No longer does a deep peel denote “alabaster white” facial depigmentation with complete effacement of wrinkles. Gregory Hetter's research showed that the strength and corresponding depth of penetration of the phenol-croton oil peel can be modified by varying the concentration of croton oil. This second article in this continuing medical education series focuses on the main historical, scientific, and procedural considerations in phenol-croton oil peels.