Abstract: The progress in the investigation on anticarcinogenic activity of tea polyphenols in the world was analyzed and reviewed in this paper. The inhibitory activity of tea extracts on the human cancer cell was firstly reported by Fujiki H in 1987 in Japan. Since then, around 5000 papers on the anticarcinogenic activity of tea were published in the world. According to the published results of investigation, four stages were divided by the author. From the period of the end of 1980’s to the middle of 1990’s, the major investigation was focused on the in vitro and in vivo investigation and clinical investigation. From the period of the middle of 1990’s to the beginning of 21 Century, the major investigation was focused on the epidemiological investigation and the anticarcinogenic mechanism. Since the beginning of 21^st Century, investigation was continuing on the anticarcinogenic mechanism on the first hand, and the metabolism and fate of catechins in the animal and human body were investigated. Since 2004, the investigation on the modification of chemical structure of tea catechins was conducted for the purpose of improving the bioavailability, stability and bioactivity of tea catechins in human body. This paper is mainly reviewed from the published literature after 2003 from the following five parts: results on the epidemiological investigations, anticarcinogenic mechanism, the active components of anticarcinogenic activity in tea, results on the metabolism and fate of tea catechins in animal and human body, modification of chemical structure of tea catechins and its bioavailability and bioactivity.

Key words: tea, anticarcinogenic mechanism, tea polyphenols, catechins