The devil’s claw tuber contains three important constituents belonging to the iridoid glycoside family: harpagoside, harpagide, and procumbide. The secondary tubers of the herb contain twice as much harpagoside as the primary tubers and are the chief source of devil’s claw used medicinally.³ Harpagoside and other iridoid glycosides found in the plant may be responsible for the herb’s anti-inflammatory and analgesic actions. However, research has not entirely supported the use of devil’s claw in alleviating arthritic pain symptoms.^{4, 5} In one trial it was found to reduce pain associated with osteoarthritis as effectively as the slow-acting analgesic/cartilage-protective drug diacerhein.⁶ One double-blind study reported that devil’s claw (600 or 1200 mg per day) was helpful in reducing low back pain.⁷

Devil’s claw is also considered by herbalists to be a potent bitter. Bitter principles, like the iridoid glycosides found in devil’s claw, can be used in combination with carminative (gas-relieving) herbs by people with indigestion, but not heartburn.