Onion, scientific name Allium cepa, which is eaten fresh (scallion) or dried, in its head (bulb), belongs to the Liliaceae or Liliaceae family. Red onion, also called Spanish onion or purple onion, is a type of onion vegetable. With a red, almost purple skin and red fibrous white flesh, the red onion is thought to be the most widely cultivated species of the Allium genus. With a very mild, sweet flavor, red onions are the most popular type of onion in India, the Mediterranean and the Middle East, but the most common type of onion in the UK is white onion.

While most children dislike the pungent and bitter taste of onions, most adults use it regularly. Red onions contain twice as many antioxidants as other onion varieties, making them a powerful part of an anti-inflammatory diet and lifestyle. Red onion can be used in salads, hot soups and olive oil dishes. The delicious caramelization that happens when sautéed is due to the onion's high sugar content.