Quercetin is a flavonoid, a natural pigment present abundantly in many fruits, vegetables, and red wine. It’s anti-inflammatory, and antioxidants help to prevent several diseases. Quercetin is known to control blood sugar, help reduce swelling, kill cancer tissues, and prevent bladder infections and heart diseases. Humans cannot make Quercetin in their bodies. Hence, they take it in supplements or add fruits, vegetables, and plants containing the natural pigment in their diet as it functions as antioxidants within the body.