[Past, present and future of green tea: from pleasant beverage to drug in pills?]

During the 17th century, new drinks entered the European market: wine and beer, which were largely widespread among the different European countries, were joined by coffee and tea; their consumption at was first limited to the higher classes, but they soon became popular at all levels of society. Even if their therapeutic effects were strongly stressed from different points of view, at first they encountered a certain resistance. Tea, in particular, represented a sort of compromise between a pleasant habit, bound to economic and social reasons, and a therapeutic scope. Green tea is unfermented tea. In Japan the most frequently used method of production is steaming, that deactivates the oxidase in tea leaves, determining the retention of a brilliant green colour. Its use has been proposed in a number of clinical conditions and pathologies, even if its putative therapeutic properties must be further assessed in rigorously designed and conducted clinical trials. Aim of this paper is to call needed attention to the potential role of green tea extracts in prevention and in therapy in relation to the scientific methodology of clinical research.