Objective: Polyphenols from various plants have been demonstrated as potent anti-proliferative agents to many cancer types including colorectal carcinoma.The mean aim of this report is to investigate the efficacy ofpolyphenols from tea and longan flower extracts on different colorectal carcinoma cell lines.Methods: Polyphenols were extracted from oolong tea and longan flower by hot water.The tea extract was further fractionated by membrane separation.Anti-proliferative activity of polyphenolics against colorectal carcinoma cell line SW480, HT-29 and Colo 320DM was assessed by trypan blue exclusion assay.Polyphenol treated cells were stained with propidium iodide, and rhodamin123 respectively and followed by flowcytometry analysis to determine the cell cycle distribution and mitochondria membrane potential of treated cells.DNA fragmentation assay was used to determine the apoptosis of the treated cells.Results: Catechins in various tea fraction and proanthoeyanidins-rich longan flower extracts exhibited anti-proliferative activity to HT-29 at dose-and time-dependent manner.The medium MW fraction of oolong tea showed better inhibitory efficacy than catechin and high MW fraction.Longan flower also shown strong S phase blocking activity at the concentration of 100mg/L to 400mg/L to SW480 and Colo 320DM.The mitochondria membrane potential of treated cells was also loss and generated obvious DNA fragments at the same concentration to these two cell lines.The inhibitory mechanisms of tea polyphenolics on the proliferation of colorectal cancer cell lines are ongoing.Conclusion: Longan flower extract shows strong inhibition effect of cell proliferation and DNA synthesis activity to the tested colorectal cancer cell lines.The anti-proliferation activity also comes from the apoptosis induction, which effect may be mediated by mitochondria pathway.Medium polymerized tea polyphenolics also shows the anti-proliferative activity to HT-29.Whether the anti-proliferation effect of both tea polyphenols to colorectal carcinoma cells is systemic and the detail cellular and molecular mechanisms of the effects are ongoing issue in our research group.Longan flower and fractionated tea polyphenols were potential natural pharmaceutical for coloreetal cancer.