Onion is used for treating digestion problems including loss of appetite, upset stomach, and gallbladder disorders; for treating heart and blood vessel problems including chest pain (angina) and high blood pressure; and for preventing “hardening of the arteries” (atherosclerosis). It is also used for treating sore mouth and throat, whooping cough, bronchitis, asthma, dehydration, intestinal gas, parasitic worms, and diabetes. Some people use it as a diuretic to increase urine output.