Although most often not used specifically as a medicinal herb, the onion has a wide range of beneficial actions on the body and when eaten (especially raw) on a regular basis will promote the general health of the body. The bulb is anthelmintic, antibiotic, anti-inflammatory, anti-microbial, antirheumatic, antisclerotic, antiseptic, antispasmodic, carminative, depurative, digestive, diuretic, expectorant, febrifuge, fungicidal, hypocholesterolemic, hypoglycemic, hypotensive, lithontripic, stomachic, stimulant, rubefacient, antiviral, antibacterial, tonic, and vermifuge among others.

 

For medicinal purposes, onions may be used both internally and externally. Onion (Allium cepa) and other alliaceous vegetables are similar in many respects to garlic. Internal use of onion increases circulation and stimulates and warms the body. Onion is effective against many bacteria including Bacillus subtilis, Salmonella, and E. coli. Externally, onion is used in the form of poultices for tumors and earaches. The tear-evoking lachrymatory chemical released when onion is crushed or cut has a stimulating effect on the mucosa and secretory glands of the eyes and nose has resulted in onion being selected for use as a treatment for respiratory problems.¹⁴

 

Culpeper in "The Complete Herbal" states: "……they have gotten this quality, to draw any corruption to them, for if you peel one, and lay it upon a dunghill, you shall find it rotten in half a day, by drawing putrefaction to it; then, being bruised and applied to a plague sore, it is very probable it will do the like. Onions are flatulent, or windy; yet they do somewhat provoke appetite, increase thirst, ease the belly and bowels, provoke women's courses, help the biting of a mad dog, and of other venomous creatures, to be used with honey and rue, increase sperm, especially the seed of them. They also kill worms in children if they drink the water fasting wherein they have been steeped all night. Being roasted under the embers, and eaten with honey or sugar and oil, they much conduce to help an inveterate cough, and expectorate the tough phlegm. The juice being snuffed up into the nostrils, purges the head, and helps the lethargy, (yet the often eating [of] them is said to procure pains in the head). It hath been held by divers country people a great preservative against infection to eat Onions fasting with bread and salt. As also to make a great Onion hollow, filling the place with good treacle, and after to roast it well under the embers, which, after taking away the outermost skin thereof, being beaten together, is a sovereign salve for either plague or sore, or any other putrefied ulcer. The juice of Onions is good for either scalding or burning by fire, water, or gunpowder, and used with vinegar, takes away all blemishes, spots and marks in the skin: and dropped in the ears, eases the pains and noise of them. Applied also with figs beaten together, helps to ripen and break imposthumes, and other sores."¹⁵

 

The regular consumption of raw onions has, like garlic, been shown to lower high cholesterol levels and high blood pressure, both of which help prevent atherosclerosis and diabetic heart disease, and reduce the risk of heart attack or stroke. These beneficial effects are likely due to onion’s sulfur compounds, its chromium and its vitamin B6, which helps prevent heart disease by lowering high homocysteine levels, another significant risk factor for heart attack and stroke. Onions have been singled out as one of the small number of vegetables and fruits that contributed to the significant reduction in heart disease risk seen in a meta-analysis of seven prospective studies. Of the more than 100,000 individuals who participated in these studies, those who diets most frequently included onions, tea, apples and broccoli—the richest sources of flavonoids—gained a 20% reduction in their risk of heart disease.¹⁶

 

Onions contain a number of sulfides similar to those found in garlic which may lower blood lipids and blood pressure. In India, communities that never consumed onions or garlic had blood cholesterol and triglyceride levels substantially higher, and blood clotting times shorter, than the communities that ate liberal amounts of garlic and onions. Onions are a rich source of flavonoids, substances known to provide protection against cardiovascular disease. Onions are also natural anticlotting agents since they possess substances with fibrinolytic activity and can suppress platelet-clumping. The anticlotting effect of onions closely correlates with their sulfur content.¹⁷

 

Recent researches in the West have established onion as an effective preventive food item against heart attack. Dr. N.N. Gupta of the K.G. Medical College, Lucknow, in 1966, and a panel of doctors in England in 1968 have stated that onion has been found helpful and beneficial in diseases of the heart. According to them these benefits are due to the presence of essential oil, aliypropyl disulphide, catechol, protocatechnic acid, thiopropiono aldehyde, thiocyanate, calcium, iron, phosphorus and vitamins in onion.¹⁸

 

Dr. N. Radhakrishnan, Principal of the Trivandrum Medical College and Dr. K. Madhavan Kutty have established, after seven years of research, that to get rid of coronary heart or blood pressure disorders one should take 100 grams of onion per day. They concluded that onions are very valuable in heart diseases as they correct thrombosis and also reduce blood cholesterol.¹⁹

 

The regular consumption of onions, as little as two or more times per week, is associated with a significantly reduced risk of developing colon cancer. The constituent diallyl disulfide possesses inhibitory properties against colon and renal cancers. The organosulfur compounds contained in onion exert chemopreventive effects on chemical carcinogenesis.²⁰

 

 

Onions contain a number of flavonoids, the most studied of which, quercitin, has been shown to halt the growth of tumors in animals and to protect colon cells from the damaging effects of certain cancer-causing substances. Cooking meats with onions may help reduce the amount of carcinogens produced when meat is cooked using high heat methods.

 

Onions are a very rich source of fructo-oligosaccharides. These oligomers stimulate the growth of healthy bifidobacteria and suppress the growth of potentially harmful bacteria in the colon. In addition, they can reduce the risk of tumors developing in the colon.

 

In central Georgia where Vidalia onions are grown, mortality rates from stomach cancer are about one-half the average level for the United States. Studies in Greece have shown a high consumption of onions, garlic and other allium herbs to be protective against stomach cancer.

 

Chinese with the highest intake of onions, garlic, and other Allium vegetables have a risk of stomach cancer 40 percent less than those with the lowest intake. Elderly Dutch men and women with the highest onion consumption (at least one-half onion/day) had one-half the level of stomach cancer compared with those consuming no onions at all.²¹

 

Making onion and garlic a staple in your healthy way of eating may greatly lower your risk of several common cancers, suggests a large data set of case-control studies from Southern European populations. Study participants consuming the most onions showed an 84% reduced risk for cancer of the oral cavity and pharynx, 88% reduced risk for esophageal cancer, 56% reduced risk for colorectal cancer, 83% reduced risk for laryngeal cancer, 25% reduced risk for breast cancer, 73% reduced risk for ovarian cancer, 71% reduced risk for prostate cancer, and 38% reduced risk for renal cell cancer, compared to those eating the least onions.²²

 

The thiosulfinates in Onion exhibit antimicrobial properties. These compounds are effective in killing many common bacteria, including Salmonella typhi, Pseudomonas aeriginosa, and Escherichia col (E. coli). Onion is not as potent as garlic since the sulfur compounds in onion are only about one-quarter the level found in garlic. As well as being the principle flavor, allicin is also a powerful antibiotic that can avert food poisoning and gastritis. The essence of onion is also used to combat food poisoning from E. coli and salmonella bacteria.²³

 

Consumption of onions may prevent gastric ulcers by scavenging free radicals and by preventing growth of the ulcer-forming microorganism, Helicobacter pylori. The use of onions stimulates the process of peristalsis (contraction and expansion) of the intestines and removes intestinal putrefaction and flatulence. It is also useful in indigestion and biliousness.²⁴

 

Onion possesses expectorant properties and has effective germicidal properties. On account of its content of a volatile oil, the onion is very useful in respiratory disorders. The onion dislodges mucus and prevents its fresh formation. It liquifies phlegm and prevents its further formation. It has been used as a food remedy for centuries in cold, cough, bronchitis and influenza. Onions relieve nasal and chest congestion. Herbalist, David Christopher teaches that chopped roasted onions be placed on the chest for congestion. Onions, both cooked and raw, are an especially good addition to foods during the cold and flu season. Onions induce perspiration to "sweat out a cold." It is one of the safest preventive medicines against common cold during winter. In his book, George Washington recommended eating raw onions to fight off colds.²⁵

 

Onion is anti-allergenic, due to its content of quercetin. The quercetin of onions is absorbed through the lining of the intestine in about 20 minutes, compared to 20 hours for many other foods (including apples), and stays in circulation longer than quercetin from other foods.²⁶

 

Several anti-inflammatory agents in onion render them helpful in reducing the severity of symptoms associated with inflammatory conditions such as the pain and swelling of osteo- and rheumatoid arthritis, the allergic inflammatory response of asthma, as well as the respiratory congestion associated with the common cold. Onion contains compounds that inhibit lipoxygenase and cyclooxygenase (the enzymes that generate inflammatory prostaglandins and thromboxanes), thus markedly reducing inflammation. Onions’ anti-inflammatory effects are due not only to their vitamin C and quercitin, but to other active components called isothiocyanates. These compounds work synergistically to spell relief from inflammation.

 

The higher the intake of onion, the lower the level of glucose found during oral or intravenous glucose tolerance tests. Experimental and clinical evidence suggests that allyl propyl disulfide is responsible for this effect and lowers blood sugar levels by increasing the amount of free insulin available. Allyl propyl disulfide does this by competing with insulin, which is also a disulphide, to occupy the sites in the liver where insulin is inactivated. This results in an increase in the amount of insulin available to usher glucose into cells causing a lowering of blood sugar.

 

In addition, onions are a very good source of chromium, the mineral component in glucose tolerance factor that helps cells respond appropriately to insulin. Clinical studies of diabetics have shown that chromium can decrease fasting blood glucose levels, improve glucose tolerance, lower insulin levels, and decrease total cholesterol and triglyceride levels, while increasing good HDL-cholesterol levels. Marginal chromium deficiency is common in the United States. This is not surprising since chromium levels are depleted by the consumption of refined sugars and white flour products. One cup of raw onion contains over 20% of the Daily Value for this important trace mineral.

 

Onions also help maintain healthy bones, suggests a study published in the Journal of Agricultural and Food Chemistry. A compound newly identified in onions with the long complex name of gamma-L-glutamyl-trans-S-1-propenyl-L-cysteine sulfoxide, GPCS for short, inhibits the activity of osteoclasts (the cells that break down bone). The more GPCS given in this animal study, the more the bone resorptive (breakdown) action of osteoclasts was inhibited.

 

Onions may be especially beneficial for women, who are at increased risk for osteoporosis as they go through menopause. Fosamax (Alendronate), one of the drugs typically prescribed to prevent excessive bone loss, works in a similar manner, by destroying osteoclasts, so they do not break down bone. Potential negative side effects of Fosamax include irritation of the upper gastrointestinal mucosa, acid regurgitation, esophageal ulcers and erosions among others. Potential negative side effects of eating onions: onion breath.

 

In the Middle East, both raw and cooked onions are eaten at practically every meal. An Arabian herbal recognizes them to aid deafness, ear infection, malarial fever, phlegm, skin problems, stomach cramps, and to improve vision. Onion is also used internally to relieve excess gas and calm an upset stomach. Onion, along with other herbs, is used to rid the digestive system of parasites. They also use onion to stimulate the appetite.²⁷

 

Onions are noted for their easily assimilable iron content. They are, therefore, beneficial in the treatment of anemia. The RDA of iron ranges from about 8 mg./day for an adult male to 18 mg/day for an adult female. One hundred grams of onion contains 9 milligrams of iron.²⁸

 

Onion is also useful in preventing oral infection and tooth decay. Latest researches of Russian doctors have further confirmed the bactericidal properties of onion. According to these findings, if a person consumes one raw onion every day by thorough mastication, he will be protected from a host of tooth disorders. The Russian Doctor, B.P. Tohkin, who has contributed to this research, has expressed the opinion that chewing raw onion for three minutes is sufficient to kill all the germs in the mouth. In addition, toothache is often allayed by placing a small piece of onion on the bad tooth or gum.²⁹

 

Onion is irritating to the skin and stimulates the circulation of blood in the mucous membrane. Warts also sometimes disappear if rubbed with cut onions. Roasted or otherwise, onions are applied as a poultice to indolent boils, bruises and wounds.³⁰

 

In traditional herbal medicine, onion is a gentle herb for relieving toxicity and breaking up areas of infections like sores or abscesses. It has anti-microbial qualities and has been used in wound treatment. A poultice of hot onions is effective for abscesses. Baked onions can be used as a poultice to remove pus from sores.³¹

 

Fresh onion juice is a very useful first aid treatment for bee and wasp stings, bites, grazes or fungal skin complaints. It also aids the formation of scar tissue on wounds, thus speeding up the healing process, and has been used as a cosmetic to remove freckles. Raw and bruised onions have been used for sprains, bruises, and unbroken chilblains (minor frostbite).³²

 

Onion juice dipped on cotton wool and put into the ear is a popular Russian remedy for ringing sound in the ears. When warmed the juice can be dropped into the ear to relieve earache. Roasted onions are also used as a poultice for earaches.³³

 

Onions are highly valued herbs possessing culinary and medicinal value. Some of their beneficial properties are seen after long-term usage. Liberal use of onions can play a protective role against the development of many health problems in addition to adding flavor to our food.

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¹⁴ Andrews University, Nutrition Department, "Onions are Beneficial for Your Health" www.vegetarian-nutrition.info/updates/onions, accessed 14 May 2007.

¹⁵ Nicholas Culpeper, The Complete Herbal, "Onions," www.bibliomania.com, accessed 02 May 2007.

¹⁶ C. Galeone, C. Pelucchi, et al, "Onion and Garlic Use and Human Cancer," American Society for Nutrition,  American Journal of Clinical Nutrition,  www.ajcn.org/cgi/content/abstract, accessed 02 May 2007.

¹⁷ Food that Heal, "Onion—Heart Disease,” www.indiangyan.com, accessed 20 May 2007.

¹⁸ Ibid.

¹⁹ Ibid.

²⁰ The source for this paragraph and the next three paragraphs is The George Mateljan Foundation, The World's Healthiest Foods, "Onions—Health Benefits,” www.whfoods.org, accessed 15 May 2007.

²¹ Food that Heal, "Onion—Heart Disease,” www.indiangyan.com, accessed 20 May 2007.

²² C. Galeone and C. Pelucchi, et al, "Onion and Garlic Use and Human Cancer," American Society for Nutrition,  American Journal of Clinical Nutrition, Vol. 84, No. 5, pg. 1029-1030, Nov. 2006, www.whfoods.org, accessed 12 May 2007.

²³ Andrews University, Nutrition Department, "Onions are Beneficial for Your Health," www.vegetarian-nutrition.info/updates/onions, accessed 14 May 2007.

²⁴ The George Mateljan Foundation, The World's Healthiest Foods, "Onions—Health Benefits,” www.whfoods.org, accessed 15 May 2007.

²⁵ Food that Heal, “Onion––Respiratory Disease,” www.indiangyan.com, accessed 20 May 2007.

²⁶ The source for this paragraph and the next five paragraphs is from The George Mateljan Foundation, The World's Healthiest Foods, "Onions—Health Benefits,” www.whfoods.org, accessed 15 May 2007.

²⁷ S. A. Ghazanfar, CRC Handbook of Arabian Medicinal Plants, Boca Raton, FL: CRC Press, Inc., 1994, 265 pp., www.ars-grin.gov/duke/, accessed 15 May 2007.

²⁸  Food that Heal, “Onion—Anemia,” www.indiangyan.com, accessed 20 May 2007.

²⁹ Dr. H.K.Bakhru, Nature Cure for Children's Diseases, “Treatment,” from the Reading Room of www.healthlibrary.com, accessed on 22 May 2007.

³⁰ Food that Heal, “Onion––Skin Disorders,” www.indiangyan.com, accessed 20 May 2007.

³¹ Dr. John R. Christopher, Herbal Home Health Care, Christopher Publications, 2004, pgs. 31-32.

³² Plants for a Future, Edible, Medicinal and Useful Plants for a Healthier World, “Allium cepa –– L. Onion, Other Uses,” www.pfaf.org/database/plants.php?Allium+cepa, accessed 22 May 2007.

³³ Plants for a Future, Edible, Medicinal and Useful Plants for a Healthier World, “Allium cepa –– L. Onion, Medicinal Uses,” www.pfaf.org/database/plants.php?Allium+cepa, accessed 22 May 2007.