The dried gum-resin is the best known botanical derived from the tree; the resin and its extract contain a large amount of boswellic acid and its derivatives, which have been used traditionally as analgesics to treat joint pain, arthritis, and other forms of rheumatism.25 A single in vitro study showed how boswellic acid and its derivatives can inhibit various P450 cytochromes, namely CYP1A2, CYP2C9, CYP2C19, and CYP2D6.26 However, since there are no clinical studies in the literature, the significance of these interactions is questionable. Here, CYP2C9 is linked to arthritic joint disease.