Staphylea preparations are used in TCM and have been used by native Americans for a number of indications, such as rheumatism. Based on this knowledge, the anti-inflammatory activity of light petroleum extracts of leaves of Staphylea colchica Stev., S. elegans Zab., S. holocarpa Hemsl. and S. pinnata L. has been determined using in vitro assays for inhibition of cyclooxygenase (COX-1 and COX-2) and leukotriene B4 (LTB4) formation by lipoxygenase (5-LOX). All extracts inhibited COX-1 and COX-2, with S. holocarpa and S. elegans performing best. Inhibition of LTB4 formation was less pronounced. As unsaturated fatty acids are known to inhibit arachidonic acid metabolism in vitro, the fatty acid content was determined of the active extracts and set in correlation with their activity. Unsaturated fatty acids were found to contribute to the observed COX-2 and LTB4 formation inhibitory activity to a different extent.