Eupatilin (5,7-dihydroxy-3',4',6-trimethoxyflavone) is the major lipophilic flavonoid from Artemisia umbelliformis Lam. and Artemisia genipi Weber, two mountain wormwoods used for the production of the celebrated alpine liqueur genepy. The topical anti-inflammatory activity of eupatilin was investigated using the inhibition of the Croton-oil-induced dermatitis in the mouse ear as the end point. The oedematous response and the leukocyte infiltration were evaluated up to 48 h after the induction of phlogosis, comparing eupatilin with hydrocortisone and indomethacin as representatives of steroid and non-steroid anti-inflammatory drugs, respectively. At maximum development, eupatilin significantly reduced edema in a dose-dependent manner (ID(50) = 0.28 micromol/cm(2)), showing an anti-inflammatory potency comparable to that of indomethacin (ID(50) = 0.26 micromol/cm(2)) and only 1 order of magnitude lower than that of hydrocortisone (ID(50) = 0.03 micromol/cm(2)). Within 48 h, eupatilin (0.30 micromol/cm(2)) caused a global inhibition of the oedematous response (42%) higher than that of an equimolar dose of indomethacin (18%) and fully comparable to that of 0.03 micromol/cm(2) of hydrocortisone (55%). Moreover, the effect of eupatilin on the granulocytes infiltrate (32% inhibition) was similar to that of indomethacin (35% inhibition) and comparable to that of hydrocortisone (42% reduction), as confirmed by histological analysis. When our results are taken together, they show that eupatilin is endowed with potent in vivo topical anti-inflammatory activity, qualitatively similar to that of hydrocortisone and intermediate in terms of potency between those of steroid and non-steroid drugs.