Red onions are cultivars of onion with reddish purple skins and whose white flesh, when raw, is tinged with red or purple. See: Onion.
A study comparing extracts of red onion to yellow and white varieties found them to have the highest content of phenolic compounds and flavonoids with antimutagenic and antioxidant properties. Red onion extracts have also shown antifungal and antibacterial effects, including against pathogenic strains and antispasmodic effects, helping to treat gastrointestinal distress. Onions are a fairly common allergen. See: Onion.
Salsa, salads, raw, prepared foods
Food and Chemical Toxicology
LWT – Food Science and Technology
Journal of Agricultural and Food Chemistry
Food and Chemical Toxicology 2