Dr. Okada(#17) has noted the fact that tobacco growers use an exudat of green tea to prevent crop damage by the tobacco mosaic virus an verified that green tea catechin suppresses the growth of this virus. I addition, Prof. Shimamura(#18) has determined that green tea catechin and theaflavin (an oxidized form of catechin) present in black tea have a stron effect on the influenza virus. Green tea catechin and black tea theaflavi directly act on the influenza virus and inactivate it. It appears, therefore, that gargling with green or black tea is very effective in preventing influenza. This effect is increased by keeping the green tea catechin and the virus in contact as long as possible.
It is also hoped that the antiviral capability of green tea catechin may have some beneficial effect on the AIDS (Acquired Immune Deficiency Syndrome) virus, which is now the world's most feared infectious disease. Dr. Nakane and Dr. Ono(#19) at the Aichi Cancer Institute have verified the fact that green tea catechin can inhibit the activity of the AIDS virus in laboratory test. Although this research is just in its nascent stage, it provides a slight ray of hope that a treatment may someday be found to combat the now unstoppable AIDS virus. Future research advances in this field are expected.

(#17) F. Okada, Chagyo Kenkyu Hokoku, 48, 52 (1978).
(#18) T. Shimamura et al., Lett. APPI. Microbiol., 11, 38 (1990).
(#19) H. Nakane and K. Ono, Biochemistry, 29, 2041 (1990).