For many years it has been known that green tea polyphenols actively suppress many bacterial, fungal and viral species. On the virus front, green tea suppresses the adenovirus, Epstein-Barr, herpes simplex, HIV-1 and influenza viruses. EGCG, one of the main polyphenols in green tea, is mainly responsible for this suppression. Specifically, ECGC binds to the hemagglutinin of the influenza virus, which blocks it from attaching to (and infecting) target receptor cells. EGCG also alters the virus cell membrane, which further inhibits its ability to infect other cells. Another important component of green tea is the amino acid L-theanine, which has been shown to activate human gamma-delta-T lymphocytes to proliferate and make interferon-gamma, a potent antimicrobial cytokine. These lymphocytes are considered to be the body's first line of defence against infection. Green tea therefore offers a two-pronged protection from the flu which vaccination simply cannot match. But for final proof, we need clinical trials.