It’s said that it was the Chinese Emperor Shen Nong (2737 BC) who discovered the beneficial properties of tea leaves set in infusion and who consequently fostered the cultivation of Camellia Sinensis. From 200 BC tea was included in the traditional herbals as a plant useful for the treatment of fatigue and digestive disorders. There is no doubt that its salubrious properties combined with the pleasant flavour of the drink have contributed to its popularity all over the world. Ongoing research in the medical sphere has meant that in recent decades it has been possible to identify the main chemical constituents contained in tea leaves, thus underscoring the traditionally known properties and also discovering new ones. The data in literature, combined with in vitro and in vivo experiments appear to attribute properties beneficial to the human well-being to specific substances contained in tea.