Tea and health, tea and selenium biological effects interact with each other<3,4>(23,26,28). Selenium research involves selenium toxicity, efficacy, nutrition and enzyme targets. Selenium toxicity: Invented nano-selenium and explained its high safety (1,2,4-6,9,13,20,24,26). Based on the low toxicity characteristics of nano-selenium, the former director of the FDA Toxicology Research Center invited two editors According to the Ministry of Toxicology Monograph <1,2>, nano-selenium is a health food approved by the Ministry of Health and is a national new product. Selenium efficacy: Invented the combination of sodium selenosulfate and the first-line chemotherapy drug cisplatin to treat tumors. In liver cancer models, cisplatin achieved a cure rate of at most 25%, and the combination produced a cure rate of at least 75% (8,15,19,25 ), Cancer Weekly reported the research progress three times. Selenium nutrition: Selenium and sulforaphane in broccoli were found to synergistically induce thioredoxin reductase, and selenium and broccoli may be anti-cancer partners (3), BBC News, The Times, The Guardian, Genomics and Genetics Weekly, Cancer Weekly reported this finding. Selenase target: Based on animal experiments, it has been shown that thioredoxin reductase is a drug target and a toxic target of anti-cancer drugs (7,11,12,17,18,21,27). Threshold Pharmaceuticals of the United States is invited to evaluate new anti-cancer drugs. TH-302 pharmacology, it was found to inhibit the activity of this enzyme (22).