Onion

How each use is prepared

Parts used: bulb, leaf.

• Obesity management

  Traditional use

  Other · as reported in a Nigerian ethnobotanical survey

  People use it this way, but it has not been tested.

  A 2025 ethnobotanical survey of the North Central zone of Nigeria records onion (Hausa name Albasa) among plants used for managing obesity. A survey shows that people use the plant for this purpose. It does not show that onion reduces weight. The category is "other" because obesity has no category in the schema. The survey's preparation details are not used here because the table layout in the opened text was ambiguous. ^[4]

• Boils, wounds and stings

  Traditional use

  Wounds

  People use it this way, but it has not been tested.

  PROTA reports external use of onion for boils, felons (painful infections of a finger), wounds and stings. It is a compilation of traditional use. The opened text gives no experimental study for these uses. Do not use onion in place of medical care for a wound or infection. ^[1]

• Coughs and bronchitis

  Traditional use

  Cough and breathing · as reported in traditional use

  People use it this way, but it has not been tested.

  PROTA reports internal use of onion for coughs, bronchitis, asthma and digestive disorders. The opened text gives no clinical study for these uses. A cough or breathing problem, especially in a child or in someone with asthma, needs a health worker's assessment. ^[1]

• Blood sugar in diabetes

  Lab or animal studies

  Blood sugar · laboratory and review evidence

  Tested in the laboratory or in animals, not in people.

  A 2026 review of antidiabetic plants from the ECOWAS region lists onion among its remedies, and a 2025 review reports anti-hyperglycaemic (blood-sugar-lowering) effects of onion. The 2025 review says these claims are mostly from preclinical (laboratory or animal) work or are review-level. The evidence in the sources read is therefore weak, and no human trial of onion for blood sugar was opened. Do not use onion in place of prescribed diabetes medicine. ^[5][6]

• Infections

  Lab or animal studies

  Infections · reported antibacterial property of sliced raw onion

  Tested in the laboratory or in animals, not in people.

  PROTA reports that sliced raw onions have antibiotic activity. A 2025 review reports antimicrobial effects of onion, mostly from laboratory work. The evidence is weak. Onion is not a substitute for treatment of a bacterial or parasitic infection. ^[1][6]

About this plant

Onion is a cultivated plant recorded in traditional use for coughs, boils and wounds, and laboratory and review studies report blood-sugar and antibacterial effects. The sources read give no safety data for people, so safety is not established for any use, and onions are toxic to dogs.

How to recognise it

Onion is a biennial herb, a plant that lives two years and usually flowers in its second year, and it is grown as an annual in practice. The plant can reach about 100 cm in height. Its leaves are hollow, D-shaped in cross-section (flat on one side and round on the other when cut across), and number 3 to 8 per plant. The flowers form a round cluster (a spherical umbel, a head of flower stalks that spread from one point) up to 8 cm across. PROTA lists shallot as a common name for this plant. The sources read do not describe the bulb in detail or describe seeds.

Where it grows

PROTA says the species is only known from cultivation. Wild populations are not documented in the sources read.

In Nigeria

GBIF holds 49 occurrence records from Nigeria for this species. PROTA lists Nigeria among bulb-onion production areas. That describes cultivation, not native range. The sources read do not name Nigerian states or regions for onion.

Scientific details

Scientific name

Allium cepa L.

Family

Amaryllidaceae

Main compounds

propenyl cysteine sulphoxide, (Z)-thiopropanal-S-oxide, quercetin, anthocyanins

Sources

Not yet reviewed Drafted with AI from the sources below. Treat with care.

1. Allium cepa (PROTA). PROTA (Plant Resources of Tropical Africa), Wageningen.
2. GBIF backbone. Allium cepa L. - GBIF species match (accepted, Amaryllidaceae). Global Biodiversity Information Facility.
3. GBIF occurrence search, Allium cepa, country NG (49 records). Global Biodiversity Information Facility.
4. Anyanwu et al.. An Ethnobotanical Survey and Pharmacological and Toxicity Review of Medicinal Plants Used in the Management of Obesity in the North Central Zone of Nigeria. Journal of Obesity, 2025. PMID 40026359.
5. Ohouko et al.. Diabetes mellitus in ECOWAS: an overview of the safety and efficacy of medicinal plants used in traditional medicine practices. Tropical Medicine and Health, 2026. PMID 41872917.
6. Bedir, Almasri, Azar, et al.. Exploring the Therapeutic Potential of Allium cepa and Allium sativum Extracts: Current Strategies, Emerging Applications, and Sustainability Utilization. Biology, 2025. PMID 40906415.
7. Biasibetti et al.. Fatal Garlic (Allium sativum) Toxicosis in a Dog: Gross and Histopathological Findings in a Rare Case of Systemic Hemolytic Injury. Animals (MDPI), 2026. PMID 42278144.