Prostaglandins (PGs) are arachidonic acid metabolites produced by the action of the enzyme cyclooxygenase (COX). Although PGs are important mediators of inflammation in various diseases, The deciduous herb, Salix mucronata Thunb (commonly called cape silver willow or safsaf willow), is widely distributed along the Nile River in Egypt. Like other willow trees, extracts from safsaf have also been used in traditional medicine. The antiinflammatory effects of Salix mucronata are the inhibition of cyclooxygenase-1 (COX-1) and cyclooxygenase-2