Quercetin is a plant flavonoid found in foods like onions, apples (peel), capers, and tea. It is studied for anti-inflammatory and antioxidant actions and for potential modulation of allergic pathways (including mast-cell related responses). In humans, outcomes depend strongly on the formulation, dose, and duration; it is not a “miracle cure” and works best when aligned with a clear goal and a solid lifestyle foundation. If supplementation is considered, a time-limited, goal-driven plan and medication-interaction screening are prudent.