This study was carried out to evaluate antitoxic effects of Houttuynia cordata extract on cadmium by colorimetric methods. The antitoxic activity ofc in NIH 3T3 fibroblasts was evaluated by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) and SRB (sulforhodamine B protein) assays. The light microscopic study was carried out to observe morphological changes of the treated cells. The concentration of 10-2 mg/ml of Houttuynia cordata extract was shown significant antitoxic activity. The number of NIH 3T3 fibroblasts were antitoxic and tend to regenerate. These results suggest that the ethyl acetate extract of Houttuynia cordata retains a potential antitoxic activity.