Onion is a plant. The bulb (rounded underground part) of the onion is used to make medicine.
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.
Onion is applied directly to the skin for insect bites, wounds, light burns, boils, warts, and bruises.
In foods, onion is used in many recipes.
In manufacturing, the oil is used to flavor foods.
How it works
Onion might help reduce cholesterol levels, a risk factor for hardening of the arteries. There is some evidence that onion might also reduce lung tightness in people with asthma.
Most research suggests that applying onion extract, usually as a specific product containing heparin and allantoin (Contractubex), to the skin for 10 weeks to 6 months improves scar color and appearance, as well as pain and itching, in people with scars due to burns, tattoo removal, injuries, or surgical removement of tissue. However, using a specific product containing onion exract and allantoin (Mederma, Merz Pharmaceuticals) for 4-11 weeks does not seem to improve the appearance of new surgical scars.
Onion is LIKELY SAFE when taken by mouth in amounts commonly found in food or when applied to the skin
It is POSSIBLY SAFE for most people when taken by mouth in larger amounts. Taking up to a maximum of 35 mg of the onion ingredient “diphenylamine” per day for several months seems to be safe.
Pregnancy and breast-feeding: There is not enough reliable information about the safety of taking onion as a medicine if you arepregnantorbreast-feeding. Stay on the safe side and avoid using onion in amounts larger than usual food amounts.Are there any interactions with medications?
Bleeding disorder: Onion might slow blood clotting. There is concern that onion might increase the risk of bleeding when taken as a medicine. Don't use medicinal amounts of onion or onion extract if you have a bleeding disorder.
Diabetes: Onion might lower blood sugar. If you have diabetes and use onion in medicinal amounts, check your blood sugar carefully.
Surgery: Onion might slow blood clotting and lower blood sugar. In theory, onion might increase the risk for bleeding or interfere with blood sugar control during and after surgical procedures. Stop using onion as a medicine at least 2 weeks before a scheduled surgery.
Some people are allergic to onions. Aspirin might increase your sensitivity to onions if you are allergic to onions. This has only been reported in one person. But to be on the safe side, if you are allergic to onions do not take aspirin and eat onions.Lithium
Onion might have an effect like a water pill or "diuretic." Taking onion might decrease how well the body gets rid of lithium. This could increase how much lithium is in the body and result in serious side effects. Talk with your healthcare provider before using this product if you are taking lithium. Your lithium dose might need to be changed.Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)
Some medications are changed and broken down by the liver. Onion might slow down how quickly the liver breaks down some medications. Taking onion along with some medications that are broken down by the liver might increase the effects and side effects of some medications. Before taking onion, talk to your healthcare provider if you are taking any medications that are changed by the liver.Medications that might be affected include acetaminophen, chlorzoxazone (Parafon Forte), ethanol, theophylline, and anesthetics such as enflurane (Ethrane), halothane (Fluothane), isoflurane (Forane), methoxyflurane (Penthrane), and others.Onion might decrease blood sugar. Diabetes medications are also used to lower blood sugar. Taking onion along with diabetes medications might cause your blood sugar to go too low. Monitor your blood sugar closely. The dose of your diabetes medication might need to be changed.Some medications used for diabetes include glimepiride (Amaryl), glyburide (DiaBeta, Glynase PresTab, Micronase), insulin, pioglitazone (Actos), rosiglitazone (Avandia), chlorpropamide (Diabinese), glipizide (Glucotrol), tolbutamide (Orinase), and others.Onion might slow blood clotting. Taking onion along with medications that also slow clotting might increase the chances of bruising and bleeding.Some medications that slow blood clotting include aspirin, clopidogrel (Plavix), diclofenac (Voltaren, Cataflam, others), ibuprofen (Advil, Motrin, others), naproxen (Anaprox, Naprosyn, others), dalteparin (Fragmin), enoxaparin (Lovenox), heparin, warfarin (Coumadin), and others.