The most likely side effect of devil’s claw is stomach upsets but it has also been reported to cause headaches, ringing in the ears, loss of taste and appetite. People with allergies may react to devil’s claw. Devil’s claw should not be taken by people with gastric or duodenal ulcers. People with gall stones should consult their health providers. Pregnant and breast feeding women should not take devil’s claw. Devil’s claw extracts have theoretically been associated with interactions with blood thinning agents e.g. warfarin, and cardiac drugs so it is important to talk to your health provider if you have heart disease or are taking these drugs.