Indications:
Early American settlers used wild onions to treat colds, coughs, and asthma, and to repel insects. In Chinese medicine, onions have been used to treat angina, coughs, bacterial infections, and breathing problems.

The World Health Organization (WHO) supports the use of onions for the treatment of poor appetite and to prevent atherosclerosis. onion extracts are recognized by WHO for providing relief in the treatment of bronchitis. Onions are known to decrease bronchial spasms. An onion extract was found to decrease allergy-induced bronchial constriction in asthma patients.
Onions are a very rich source of fructo-oligosaccharides. These oligomers stimulate the growth of healthy bifidobacteria and suppress the growth of potentially harmful bacteria in the colon. In addition, they can reduce the risk of tumors developing in the colon.

Onions contain a number of sulfides similar to those found in garlic which may lower blood lipids and blood pressure. In India, communities that never consumed onions or garlic had blood cholesterol and triglyceride levels substantially higher, and blood clotting times shorter, than the communities that ate liberal amounts of garlic and onions. Onions are a rich source of flavonoids, substances known to provide protection against cardiovascular disease. Onions are also natural anticlotting agents since they possess substances with fibrinolytic activity and can suppress platelet-clumping. The anticlotting effect of onions closely correlates with their sulfur content.

Onion extracts, provide some protection against tumor growth. In central Georgia where Vidalia onions are grown, mortality rates from stomach cancer are about one-half the average level for the United States. Studies in Greece have shown a high consumption of onions, garlic and other allium herbs to be protective against stomach cancer.