The present invention discloses a green tea extract having modified constituent content, which exhibits reduced hepatotoxicity, and a composition comprising same as an active ingredient for enhancing blood circulation, inhibiting lipid accumulation in hepatocytes, inhibiting gingivalis bacteria, or increasing cerebral blood flow. Specifically, a green tea extract according to an aspect of the present invention has constituents that are modified by treatment at a high temperature to thus have lower concentration of that which causes hepatotoxicity than conventional green tea extract, thereby allowing hepatocyte damage to be reduced. The composition comprising such a green tea extract according to the present invention is of high safety even when being ingested in large amounts and exhibits excellent efficacy in enhancing blood circulation, inhibiting lipid accumulation in hepatocytes, inhibiting gingivalis bacteria, or increasing cerebral blood flow.
