For centuries, consumption of green tea was known anecdotally to alleviate symptoms from a wide variety of ailments. In the 1906 classic The Book of Tea, Japanese scholar Okakura Kakuzo tells us that tea "was highly prized for possessing the virtues of relieving fatigue, delighting the soul, strengthening the will, and repairing the eyesight." In the 1940s and 1950s, research on the chemical composition of the tea plant (Camellia sinensis) revealed a powerful antioxidant, epigallocatechin gallate (EGCG), as the major polyphenolic constituent and the substance most likely responsible for conferring health benefits. This early work led to an explosion in research on green tea polyphenols, with a recent human clinical trial suggesting their potential in the treatment of chronic lymphocytic leukemia. It seems the drink that "began as a medicine and grew into a beverage" may have finally come full circle.