The topical anti-inflammatory activity of a germacrane derivative [1,4-dihydroxy-germacra-5E-10(14)-diene; DHGD] isolated from Achillea pannonica Scheele (Asteraceae) was investigated employing the Croton oil-induced dermatitis in the mouse ear. Its effects on the oedematous response and on leukocytes infiltration are described. The germacrane derivative significantly inhibited ear oedema in a dose-dependent manner, with an ID(50) of 0.40 micromol/cm(2). DHGD (0.75 micromol/cm(2)) provoked a global inhibition of the oedematous response (61 %) higher than that induced by an equimolar dose of indomethacin (43 %) within 24 hours; the reduction induced by hydrocortisone (0.10 micromol/cm(2)) was 68 %. The effect of DHGD (61 % inhibition) was higher than that of the equimolar dose of indomethacin (51 % inhibition) also on granulocytes recruitment at the site of inflammation. Hydrocortisone (0.10 micromol/cm(2)) reduced the cellular infiltrate by 44 %.