Abstract:-Antioxidants are substances that remove, prevent or delay oxidative damage to a target molecule. Therefore, an antioxidant may act to control the level of free radicals to counteract oxidative damage. The effects of medicinal plants in prevention and treatment of many diseases have been widely attributed to their antioxidants activities. This review was designed to highlight the antioxidant effects and free radical scavenging activity of medicinal plants as a third part of our previous reviews.