Abstract: Epigallo-catechingallate (EGCG), the most abundant polyphenol and important active ingredient in green tea, is widely studied in cancer prevention and treatment. It has demonstrated various anti-cancer activities in vitro and in vivo, including induction of apoptosis, as well as inhibition of tumor cell invasion, migration, and angiogenesis. EGCG has been in the clinical stage of drug development with some findings currently available. In the present review, we systematically summarize the research advances of EGCG in cancer treatment through collection of global clinical trials and related results and discuss its safety, research efficacy, and critical challenges.