Eating a moderate amount of onions every day is beneficial to the body, as they have good anti-inflammatory and bactericidal effects, and can prevent colds and coughs. They can increase gastrointestinal motility, aid in digestion, and also have certain anticancer and antitumor effects. For people with good gastrointestinal health, about 40 grams can be eaten daily. However, they should not be consumed excessively to avoid placing a burden on the gastrointestinal tract.

Onions contain plant bactericides such as allicin, which have strong bactericidal abilities and can effectively resist influenza viruses and prevent colds. These plant bactericides, when excreted through the respiratory tract, urinary tract, and sweat glands, can stimulate the secretion of cell tubular walls at these locations, thus having expectorant, diuretic, perspiratory, and antibacterial and antiseptic effects.

Onions contain allicin, which has a strong aroma and often causes tears due to its pungent smell during processing. It is this special aroma that can stimulate the secretion of gastric acid, enhance appetite. Animal experiments also prove that onions can increase gastrointestinal tension, promote peristalsis, and thus have an appetizing effect, which is particularly effective for loss of appetite caused by atrophic gastritis, insufficient gastric motility, and indigestion.

The anticancer effects of onions come from their rich selenium and quercetin. Selenium is an antioxidant that can stimulate the immune response in the human body, thereby inhibiting the division and growth of cancer cells, and can also reduce the toxicity of carcinogens. Quercetin can inhibit the activity of cancer cells and prevent their growth. A survey shows that those who regularly eat onions have a 25% lower chance of developing gastric cancer than those who do not, and a 30% lower mortality rate due to gastric cancer.

Onions are the only plant containing prostaglandin A, and they are the only known food containing prostaglandin A. They are natural blood thinners that can dilate blood vessels, reduce blood viscosity, and thus produce a hypotensive effect, which can reduce peripheral blood flow and increase coronary blood flow, preventing thrombosis. They also counteract the effects of catecholamines and other pressor substances in the human body, promoting the excretion of sodium salts, thereby lowering blood pressure. Regular consumption is beneficial for patients with hypertension, hyperlipidemia, and cardiovascular diseases.

Onions also have a hypoglycemic effect, as they contain organic substances similar to the hypoglycemic drug meso-salicylate and can generate scopoletin, which has a powerful diuretic effect in the human body. Diabetics can effectively lower blood sugar and exert a diuretic effect by eating 25~50g of onions with each meal.