Ayurveda is a holistic medical system of traditional medicine, and Triphala is one of the most popular formulations inAyurveda. Triphala is composed of three kinds of herb, Terminalia chebula, Terminalia bellirica, and Emblicaofficinalis. Since Triphala is shown to exhibit a protective activity against ionizing radiation in mice, we investigatedits activity in HeLa cells. We found that Triphala showed the protective effects against X-radiation and bleomycin,both of which generate DNA strand breaks, in HeLa cells. Further, Triphala efficiently eliminated reactive oxygenspecies (ROS) in HeLa cells. Thus, the antioxidant activity of Triphala would likely play a role in its protective actionsagainst X-radiation and bleomycin because both agents damage DNA through the generation of ROS. Theseobservations suggested that the radioprotective activity of Triphala can be, at least partly, studied with the cellscultured in vitro. The simple bioassay system with human cultured cells would facilitate the understanding of themolecular basis for the beneficial effects of Triphala.