PROBLEM TO BE SOLVED: To provide a new extremely safe antimutagenic agent utilizing a plant of Urticaceae and having excellent antimutagenic activities.SOLUTION: The antimutagenic agent includes the plant of the Urticaceae or an extracted component thereof. Urtica platyphylla Wedd. is preferably utilized as the plant of the Urticaceae, and the aboveground part is suitably utilized as the extracting part of the plant of the Urticaceae. An extracting component such as hexane, ethyl acetate and methanol is suitably utilized as the extracting component of the plant of the Urticaceae.
