This study was condo더ed to investigate the antitoxic component in aqueous extract of Houttuynia cordata $T_{HUNB}$. The results were as follows: Generally, detoxification effects by Houttuynia cordata $T_{HUNB}$ extract increased in proportion to the extract concentrations in rats. When 40 mBtg dosage of Houttuynia cordata $T_{HUNB}$ extract was administrated, Houttynia cordata $T_{HUNB}$ extract showed the highest antitoxic effects in metallothionein induction. After the extract treatment, body weights increased in proportion to the extract concentrations. However, after 3 weeks, the body weight decreased insignificantly. From the above results, Houttuynia cordate $T_{HUNB}$ extract increased metallothionein concentration and decreased the toxicity of cadmium in rats. In vitro the antitoxic activity of aqueous extract of Houttuynia cordata $T_{HUNB}$ on NIH 373 fibroblasts was evaluated by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetra-zoliumbromide) and SRB (sulforhodamine B protein) assays. The light microscopic study was carried out to observe morphological changes of the treated cells. These results were obtained as follows; The concentration of 10$^{-2}$ mg/ml of Houttuynia cordata $T_{HUNB}$ extract was shown significant antitoxic activity The number of NIH 373 fibroblasts were increased and tend to regenerate. These results suggest that Houttuynia cordata THUNB extract retains a potential antitoxic activity.oxic activity.