Vit'All+ Quercetin 350mg 120caps is a dietary supplement based on quercetin, which is a phytonutrient that humans are unable to produce, but which is easily accessible as it is found in foods. It is found in many plants and foods, such as red wine, onions, green tea, apples, berries, Gingko biloba, St John's wort, elderberry and others. Buckwheat tea is high in quercetin. People use quercetin for medicinal purposes. Quercetin is used to treat conditions of the heart and blood vessels, including "hardening of the arteries" (arteriosclerosis), high cholesterol, heart disease and circulation problems. It is also used to increase endurance and improve athletic performance.