3-acetyl-11-keto-β-Boswellic acid is a naturally occurring pentacyclic triterpene isolated from the gum resin exudate from the stem of the tree B. serrata (frankincense). It selectively inhibits 5-lipoxygenase (IC50 = 1.5 µM) in an enzyme-directed, nonredox, and noncompetitive manner. 3-acetyl-11-keto-β-Boswellic acid and other members of the boswellic acid family have been studied for potential use in the control of inflammatory diseases, including arthritis and cancer.