Its probable ancestral home is Central Asia, where it evolved from a wild species. It was already used by the Sumerians, in Ancient Egypt, Rome, India and China. It was a very popular vegetable and, for centuries, along with salt, it represented one of the first significant spices for the lower classes, as it was used extensively for seasoning. It was used both fresh and dried in winter.

It contains allicin and other sulphur compounds, which have strong antibacterial effects, especially on mucous membranes. It acts preventively against infections, and when sliced, inhalation disinfects the mucous membranes of the nose, mouth and nasopharynx. It acts preventively against infections and disinfects the mucous membranes of the nasal and oral cavities. It lowers blood pressure and blood sugar levels, stimulates the appetite, prevents vascular and venous diseases and strengthens blood circulation.

Onion has a sweet and pungent taste and a warm nature. It enters the lung, spleen, liver and large intestine meridians. Those who suffer from eczema and acne should use it with caution. It promotes sweating and expels cold, and stimulates the appetite.