Four sesquiterpenes isolated from Jasonia glutinosa D.C. (Asteraceae), namely lucinone, glutinone, 5-epi-kutdtriol and kutdtriol, have been evaluated for their in vitro anti-inflammatory activity in cellular systems generating cyclooxygenase (COX) and 5-lipoxygenase (5-LOX) metabolites. None of the compounds assayed had a significant effect on leukotriene C₄ (LTC₄)-release from calcium ionophore-stimulated mouse peritoneal cells. However, the release of prostaglandin E₂ (PGE₂) by mouse peritoneal cells stimulated with calcium ionophore was inhibited by these compounds, although with less potency than the reference drug indomethacin (IC₅₀=0.24 µM). The IC₅₀ values of the active compounds were: lucinone 42.69 µM, glutinone 3.61 µM, 5-epi-kutdtriol 1.28 µM and kutdtriol 39 µM. Of the tested compounds, only glutinone (IC₅₀=24 µM) showed a significant effect on thromboxane B₂ (TXB₂)-release induced by calcium ionophore in human platelets, although with less potency than the reference drug ibuprofen (IC₅₀=1.27 µM).