The article provides an overview of the biological importance of quercetin, a potent antioxidant flavonoid found in various plant sources such as onions, grapes, berries, and citrus fruits. Quercetin is known for its anti-inflammatory, antihypertensive, vasodilatory, and antiobesity properties. The review highlights the role of quercetin in reducing the risk of cardiovascular diseases, metabolic disorders, and certain types of cancer by reducing oxidative stress and inhibiting low-density lipoprotein oxidation. Quercetin also exhibits anti-cancer, anti-inflammatory, and neuroprotective effects, and has been shown to reduce blood pressure and cholesterol levels. The article discusses the pharmacokinetics and clinical effects of quercetin, including its ability to modulate inflammation, protect against environmental causes of free radicals, and improve endothelial function. The authors conclude that quercetin is a versatile bioflavonoid with significant health benefits and potential therapeutic applications.The article provides an overview of the biological importance of quercetin, a potent antioxidant flavonoid found in various plant sources such as onions, grapes, berries, and citrus fruits. Quercetin is known for its anti-inflammatory, antihypertensive, vasodilatory, and antiobesity properties. The review highlights the role of quercetin in reducing the risk of cardiovascular diseases, metabolic disorders, and certain types of cancer by reducing oxidative stress and inhibiting low-density lipoprotein oxidation. Quercetin also exhibits anti-cancer, anti-inflammatory, and neuroprotective effects, and has been shown to reduce blood pressure and cholesterol levels. The article discusses the pharmacokinetics and clinical effects of quercetin, including its ability to modulate inflammation, protect against environmental causes of free radicals, and improve endothelial function. The authors conclude that quercetin is a versatile bioflavonoid with significant health benefits and potential therapeutic applications.