In traditional Chinese medicine, onion is yang food. In Ayurveda too, onion is said to stimulate the human body. Herbal medicine systems of both China and India regard onion to be beneficial to the cardiovascular system. WHO (World Health Organization) supports the use of onions to treat appetite loss and prevent atherosclerosis (hardening of arteries).
Onion and garlic are rich in sulfur compounds. They possess anti-diabetic, antibiotic, hypocholesterolemic, fibrinolytic properties (Augusti, 1996).
Allium cepa extract was shown to have anti-microbial action against Staphylococcus aureus bacteria (Eltaweel, 2013). Experiments done by Azu et al. (2006) demonstrated anti-microbial properties of onion and ginger extracts against other bacteria like Escherichia coli, Salmonella typhi (causes typhoid), and Bacillus subtillis.
The German Federal Health Agency’s Commission has approved onion as an antibacterial agent. The Commission has concluded that onion is a healthful vegetable that may have many medical benefits. The plant is rich in antioxidants, flavonoids, and phenolic compounds.
The above content has been drawn from my book Asian Herbs.