It was found that the extract of tea can inhibit the growth and proliferation of gastric adenocarcinoma and hepatocellular carcinoma cells, and the cancer cells after the action of tea can be seen under the electron microscope with the cell nucleus shrinking and the cell rupture. In vivo experiments in animals have confirmed that tea improves the immune function of tumor-bearing mice and blocks the synthesis of endogenous nitrosamine, which is a common tumor-inducing agent. Fujian Tieguanyin, flower tea, Hangzhou green tea, Shaanxi Ziyang tea, Guangxi Lingshan tea, Hainan black tea and green tea have cancer inhibiting effect. According to the survey, the incidence of cancer is lower in some tea-producing areas. The above evidence shows that tea has anti-cancer and anti-cancer effects and is a healthy and beneficial health drink. Especially for the high incidence of tumor groups (such as people with family history of tumor) and tumor patients advocate drinking tea.