The aim of this work is to shed light on the importance of medicinal plants, especially those that have extracts that have a direct effect on human health. The study and identification of botany is necessary because human life has become closely linked to the life of plants as food . In addition to using plants as food, primitive man did not stop at this point, but rather developed their use to hunt prey and also used toxic plant materials in wars. With the passage of time, the ancient man was able to link the wild plants that cover the surface of the earth and the diseases that afflict him, so he used these plants or Parts of it are for treatment. A medicinal plant is defined as one or more of its parts that contain one or more chemicals in a small or large concentration and can treat one or more specific diseases or reduce the symptoms of infection if they depend on this plant part in its natural form or through chemicals effective extracted from it. green tea)Camellia Sinensis (is one of the most important natural herbs used in this field, because its chemical compounds contain beneficial effects for the body, such as its anti-inflammatory, anti-decay, anti-bacterial, and antioxidant effects . Flavonoids play a very important role in many extracts and medical preparations and their wide use in pharmacology. They are among the high-voltage compounds that can stimulate the activities of some enzymes and can change the behavior and function of a wide range of cellular systems due to their characteristics an antioxidant; it has the action of capturing free radicals, especially hydroxyl radical . It has a high ability against free radicals that cause many diseases, as it has a protective effect on blood vessels, arteriosclerosis and hepatocytes. It also shows anti-inflammatory, allergic, gastric ulcer activity and burning fat as it has significant anti-tumor activity. We conclude from this study that green tea and some plants that contain in their extracts phenolic compounds (flavonoids) play a major role in reducing the severity of common diseases, in addition to being a good antioxidant. Keywords: Green tea, Flavonoids, Antioxidants, Free Radicals.