The objective of this study was to examine the effects of ethanol and 1,8-cineole on the transcutaneous delivery of tamoxifen and gamma-linolenic acid (GLA) as a two-pronged anti-breast cancer therapy. Formulations containing tamoxifen and varying concentrations of borage oil (approximately 25% GLA), 1,8-cineole and ethanol were prepared and the simultaneous permeation of tamoxifen and GLA determined across full-thickness pig skin using Franz-type diffusion cells over 48 h. Analysis of tamoxifen and GLA (as methyl ester) were by reverse-phase HPLC. The highest flux of tamoxifen of 488.2 +/- 191 x 10(-3) microg cm(-2) h(-1) was observed with a formulation containing 20% 1,8-cineole and 20% ethanol. The same formulation also provided the greatest flux of GLA, 830.6 x 10(-3) microg cm(-2 )h(-1). The findings from this work demonstrate the ability of 1,8-cineole and ethanol to enhance the in-vitro permeation of tamoxifen and GLA across the skin and support the plausibility of simultaneously delivering tamoxifen and GLA transcutaneously as a two-pronged anti-breast cancer system.