This review article explores the role of melatonin as a natural antioxidant in combating oxidative stress. Melatonin, a versatile molecule produced by the pineal gland and found in various tissues, has been extensively studied for its antioxidant properties. The article highlights the overwhelming evidence of melatonin's protective action against oxidative stress and its ability to scavenge a wide range of free radicals, including hydroxyl, alkoxy, and peroxyl radicals. The mechanisms involved in melatonin's antioxidant activity are discussed, with electron transfer and hydrogen transfer identified as the primary mechanisms. The chemical nature of the reacting free radical also influences the relative importance of these mechanisms. Melatonin's widespread distribution, broad-spectrum antioxidant activity, ease of transport across cellular membranes, regenerability, and minimal toxicity are emphasized as key characteristics of its antioxidant properties. The article concludes that melatonin efficiently protects against oxidative stress through various mechanisms and suggests that it could be referred to as the "chemical light of health."This review article explores the role of melatonin as a natural antioxidant in combating oxidative stress. Melatonin, a versatile molecule produced by the pineal gland and found in various tissues, has been extensively studied for its antioxidant properties. The article highlights the overwhelming evidence of melatonin's protective action against oxidative stress and its ability to scavenge a wide range of free radicals, including hydroxyl, alkoxy, and peroxyl radicals. The mechanisms involved in melatonin's antioxidant activity are discussed, with electron transfer and hydrogen transfer identified as the primary mechanisms. The chemical nature of the reacting free radical also influences the relative importance of these mechanisms. Melatonin's widespread distribution, broad-spectrum antioxidant activity, ease of transport across cellular membranes, regenerability, and minimal toxicity are emphasized as key characteristics of its antioxidant properties. The article concludes that melatonin efficiently protects against oxidative stress through various mechanisms and suggests that it could be referred to as the "chemical light of health."