The main chemical constituents of Arnica include essential oils, fatty acids, thymol, pseudoguaianolide sesquiterpene lactones, phenolic acids, flavanone glycosides, sesquiterpene lactones like arnicolide, helenaline and dihydro-helenaline, flavonoids like quercetin and quercetin glucosides, alcohols like arnidiol, arnilenediol and isoarnilenediol, carotenoids, inuline and tannins.