The purpose of this study is to investigate the impacts of bicyclo-monoterpene promoters (i.e., borneol and camphor) on the in vitro permeation of ligustrazine (LGT) through the hairless porcine dorsal skin.  Fourier transform-infrared (FT-IR), scanning electron microscope (SEM) and transdermal delivery kinetics in vitro were performed to investigate the effect of the promoters on the biophysical changes to the stratum corneum (SC), the surface changes to porcine skin and the in vitro percutaneous fluxes of ligustrazine through procine skin.  FT-IR results revealed that the peak shift and the decrease in the peak area with borneol were higher than   those with camphor.  SEM studies demonstrated that the morphological change to SC was related to the chosen enhancer.  It was observed that the SC lipid extraction with borneol and camphor led to disruption of the SC and the scutella desquamation.  Apparent density (AD) was utilized to describe the desquamation extent of the scutella.  Percutaneous fluxes of ligustrazine through porcine skin were evaluated in vitro by the Franz-type diffusion cells.  Use of borneol led to greater penetration of ligustrazine across porcine skin.  It was shown  that the permeation enhancement mechanism of bicyclo-monoterpenes to ligustrazine included extracting and disordering lipids which involved the shift changes in C-H stretching and H-bonding action between enhancers and cermaide.  The penetration capability of the hydroxy groups in bicyclo-monoterpenes was better than that of the ketone groups.