An antioxidant agent capable of easily enhancing the intake of ORAC (Oxygen Radical Absorbance Capacity) is proposed. The antioxidant agent includes tealeaf as an active ingredient for enhancing ORAC. The tealeaf is preferably plucked from tea Camellia sinensis, decaffeinated or in a powdery form having a median diameter equal to or less than 50 .mu.m. A beverage using such antioxidant agent is also proposed.