In this experiment lung carcinoma was induced by crocidolite plus benzo(a)pyrene in rat. From the cancer models, we observed that the incidence (16.0%) of lung carcinomas was lower, and the survival time (376 days) of the first case of carcinoma and the mean survival time (758 days) of the rats with carcinoma were higher in the group of rats drinking 2% green tea extract for life than in the positive group (without drinking green tea extract). The mortality ratio (0.5047) was smaller in the experimental group than in the positive control group, and the survival curve of the experimental group significantly raised up, in comparison with the positive group.