Possible anti-inflammatory effect of carvacrol was evaluated by in vitro cyclooxygenase-2 (COX-2) assay. Carvacrol inhibited production of prostaglandin E(2) catalysed by COX-2 with an IC(50) value of 0.8 microM what is practically the same concentration as the IC(50) obtained for the standard inhibitors indomethacin and NS-398 with values of 0.7 microM and 0.8 microM, respectively. The COX-1 was inhibited approximately at the same rate (IC(50) of 0.7 microM for carvacrol), which suggests non-selective inhibition of both enzyme isoforms. The results of the study demonstrate possible anti-inflammatory potential of this compound due to the inhibition of inducible COX-2 isoform.