Iron can interact with several drugs and herbal supplements. Some medications can reduce the efficiency of iron absorption and assimilation by the body. Acetohydroxamic acid which is commonly used to treat kidney stone, antacids used to treat digestive upsets, chloramphenicol, cholestyramine and colestipol, desferrioxamine and H2 blockers like cimetidine, ranitidine, famotidine, or nizatidine can interfere with the absorption of iron. On the other hand, iron supplements can interfere with the absorption of certain drugs like tetracyclines, penicillamine, mycophenolate mofetil, levothyroxine, levodopa and bisphosphonates like alendronate, etidronate, risedronate and tiludronate. People using analgesic and anti inflammatory medications like aspirin and non steroidal anti inflammatory medications should not use iron supplements until and unless they are advised to do so by their doctor. These medications can damage the mucosal lining of the intestinal tract and cause bleeding. Iron supplements can irritate the gastrointestinal tract and worsen this condition. People taking dimercaprol should also avoid taking iron supplements since this compound can combine with iron to form a harmful chemical. Dietary supplements like calcium, vitamin E, polyphenols, and soy proteins can interfere with the normal absorption of iron in the body. Vitamin B complex, riboflavin, vitamin C, citric acids, and malic acids can help increase the absorption of iron. Before using iron supplements, let your doctor know about current medications and supplements you are taking.