Green tea (Camellia sinensis) is a popular beverage with many purported health benets including antiinammatory, chemopreventative, antioxidant, sunscreen effects, and more. The active ingredients modulating those benets in green tea are polyphenols called catechins: epicatechin-3-gallate, epigallocatechin, and epicatechin are three major catechins. Epicatechin-3-gallate, EGCG (Figure 4.1) is most abundant, accounting from 50%–80% of the catechins in a cup of green tea.1 EGCG has been investigated for cosmetic and medicinal uses; Table 4.1 lists several current products containing green tea extract.