
Quercetin is widely distributed in the plant kingdom and has been shown in experimental studies to have numerous effects on the body. It is found in many often-consumed foods, including apple, onion, tea, berries, and brassica vegetables, as well as many seeds, nuts, flowers, barks, and leaves. It is also found in medicinal botanicals and is often a major component of the medicinal activity of the plant.
Quercetin appears to have many beneficial effects on human health, including cardiovascular protection, anti-cancer activity, anti-ulcer effects, anti-allergy activity, cataract prevention, antiviral activity, and anti-inflammatory effects. Quercetin is extensively employed in the Protocols section of the Complete Blood Type Encyclopedia.