In this review, we provide information on thepharmacokinetic properties of green tea catechins and their beneficial health effects. The major catechins in green tea are (-)-epicatechin (EC), its hydroxyl derivative (-)-epigallocatechin (EGC), and their gallic acid esters, (-)-epicatechin-3-gallate (ECg) and (-)-epigallocatechin-3-gallate (EGCg). We developed an analytical method for determination of the presence of green tea catechins in human serum using ion-pair HPLC with electrochemical detection to estimate the pharmacokinetic parameters of target catechins. The C max values indicated that catechin absorption was relatively low. One of the gallatedcatechins, EGCg, had a longer half-life than the non-gallatedcatechins. Green tea catechins, in particular, have attracted attention as cancer preventive agents in terms of their low toxicity and being readily available to the general population. Several epidemiological studies revealed that green tea consumption reduces cancer incidence. Numerous in vitro cell culture studies have shown that EGCg, which is defined as a major green tea catechin contributing to green tea's anticancer effects, inhibits cell growth concomitant with induction of apoptosis. We have previously found that the cell death-inhibiting gene, Bcl-xL, was decreased by EGCg. These results support the hypothesis that EGCg regulates cytoplasmic NF-κB and subsequently induction of apoptosis. Green tea consumption may also play a role in preventing other lifestyle diseases, such as cardiovascular diseases and stroke, due to its hypocholesterolemic and hypotensive activities. In conclusion, habitual green tea drinking may promote human health by preventing lifestyle-related diseases.