Polyphenon is a series of high grade green tea polyphenol extracts manufactured by the Mitsui Norin Co., Ltd. of Japan. The extracts are in part the result of a water based extraction method which begins with green tea leaves, and then involves successive steps which concentrate the catechins thought to be responsible for the health benefits of green tea. As of October 2016, 20 clinical trials have been published for Polyphenon E (16 oral and 4 topical). In 2006 the U.S. Food and Drug Administration approved as a drug an ointment containing 15% Polyphenon E for the treatment of genital and perianal warts. The product name is Veregen. To date, no oral use of the product has been approved. Many dietary supplement companies sell green tea extracts as supplements, but as such, are not allowed to make any disease treatment or prevention claims. Clinical trials 1. Joe AK, Schnoll-Sussman F, et al. Phase Ib randomized, double-blinded, placebo-controlled, dose escalation study of Polyphenon E in patients with Barrett's Esophagus. Cancer Prev Res (Phila). 2015;8:1131-7. 2. Lovera J, Ramos A, et al. Polyphenon E, non-futile at neuroprotection in multiple sclerosis but unpredictably hepatotoxic: Phase I single group and phase II randomized placebo-controlled studies. J Neurol Sci. 2015;358(1-2):46-52. 3. Kumar NB, Pow-Sang J, et al. Randomized, placebo-controlled trial of green tea catechins for prostate cancer prevention. Cancer Prev Res (Phila). 2015;8(10):879-87. 4. Crew KD, Ho KA, et al. Effects of a green tea extract, Polyphenon E, on systemic biomarkers of growth factor signaling in women with hormone receptor-negative breast cancer. J Hum Nutr Diet. 2015;28(3):272-82. 5. Garcia FA, Cornelison T, et al. Results of a phase II randomized, double-blind, placebo-controlled trial of Polyphenon E in women with persistent high-risk HPV infection and low-grade cervical intraepithelial neoplasia. Gynecol Oncol. 2014;132(2):377-82. 6. Dryden GW, Lam A, Beatty K, Qazzaz HH, McClain CJ. A pilot study to evaluate the safety and efficacy of an oral dose of (-)-epigallocatechin-3-gallate-rich polyphenon E in patients with mild to moderate ulcerative colitis. Inflamm Bowel Dis. 2013;19(9):1904-12. 7. Crew KD, Brown P, et al. Phase IB randomized, double-blinded, placebo-controlled, dose escalation study of polyphenon E in women with hormone receptor-negative breast cancer. Cancer Prev Res (Phila). 2012;5(9):1144-54. 8. Shanafelt TD, Call TG, et al. Phase 2 trial of daily, oral Polyphenon E in patients with asymptomatic, Rai stage 0 to II chronic lymphocytic leukemia. Cancer. 2013;119(2):363-70. 9. Wu AH, Spicer D,