Devil's claw tuber has been found to contain three primary constituents: the iridoid glycosides known as harpagide, harpagoside, and procumbide. These components may be responsible for the herb's analgesic (pain relieving) and anti inflammatory properties, according to French researchers. Nature's Sunshine Devil's Claw also contains bitter substances which stimulate gastric secretions to enhance digestion and may also possess some astringent, sedative, and lymphatic-stimulant qualities.