Onion

Also indexed as:Allium cepa
Onion: Main Image© Martin Wall

Related Topics

Botanical names:
Allium cepa

Parts Used & Where Grown

Like its close cousins garlic, chives, scallions, and leeks, onion is a member of the lily family (Liliaceae). It is native to Eurasia but now grows all over the world, due mostly to people bringing it with them as a staple food wherever they migrated. The French explorer Pere Marquette was saved from starvation in 1624 by eating wild onions near the present site of Chicago—the name of the city is derived from a Native American word for the odor of onions.1 The bulb of the plant is used medicinally.

  • Reliable and relatively consistent scientific data showing a substantial health benefit.
  • Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit.
  • For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support.

Our proprietary “Star-Rating” system was developed to help you easily understand the amount of scientific support behind each supplement in relation to a specific health condition. While there is no way to predict whether a vitamin, mineral, or herb will successfully treat or prevent associated health conditions, our unique ratings tell you how well these supplements are understood by the medical community, and whether studies have found them to be effective for other people.

For over a decade, our team has combed through thousands of research articles published in reputable journals. To help you make educated decisions, and to better understand controversial or confusing supplements, our medical experts have digested the science into these three easy-to-follow ratings. We hope this provides you with a helpful resource to make informed decisions towards your health and well-being.

This supplement has been used in connection with the following health conditions:

Used for AmountWhy
Type 2 Diabetes
2 to 3.5 ounces fresh onion daily2 stars[2 stars]
Onion may lower blood glucose levels and improve glucose tolerance in people with type 2 diabetes.
Asthma
Refer to label instructions 1 star[1 star]
Onion may act as an anti-inflammatory in people with asthma.
Cough
Refer to label instructions 1 star[1 star]
Onion has a long history of use for relieving coughs.
Eczema
Refer to label instructions 1 star[1 star]
Onion injections into the skin and topical onion applications have been shown to inhibit skin inflammation in people with eczema, according to one trial.
Infection
Refer to label instructions 1 star[1 star]
Onion is an herb that directly attack microbes.
Type 1 Diabetes
Refer to label instructions 1 star[1 star]
Research in laboratory animals suggests onion and its active constituents may lower blood glucose levels, raise insulin levels, reduce advanced glycation end-product (AGE) formation, and possibly prevent diabetes complications.

Traditional Use (May Not Be Supported by Scientific Studies)

Onion has been used as food for many centuries.2 Onion was also a popular folk remedy, being applied to tumors, made into a syrup for relieving coughs, or prepared in a tincture (using gin) to relieve “dropsy” (heart failure–related edema).3 It was considered a weaker version of garlic by many herbal practitioners. Like garlic, onion has a longstanding but unsubstantiated reputation as an aphrodisiac.4

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The information presented by TraceGains is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires December 2024.