AIM: To investigate the enhancement of ethanol on percutaneous permeation and topical anaesthesia of tetracaine gel. METHODS: Tetracaine (4%, w/w) gels were prepared by using 20% and 70% ethanol as penetration enhancers. Franz diffusion chamber and UV spectrophotometry were adopted in the transdermal osmotic test of isolated mouse skin. Von Frey test was used to evaluate the topical anesthetic effect of tetracaine gels. RESULTS: 20% and 70% ethanol greatly improved the percutaneous permeation of tetracaine gel (P