Sublethal doses of CdCl2(3 mg/kg iv), HgCl2(2 mg/kg iv), or NaVO3(6 mg/kg iv) did not alter the content of reduced glutathione (GSH) in the livers of mice during the 24‐h observation period. In the kidneys, a tendency to increased GSH content was seen, especially after HgCl2treatment; in lung and brain the GSH levels were significantly lowered upon the treatment with all three metals. The activities of GSH S‐transferase toward an aryl substrate (CDNB; 1‐chloro‐2,4‐dinitrobenzene) was enhanced in all tissues by the administration of HgCl2> NaVO3> CdCl2. The activity of GSH S‐transferase toward an epoxide substrate [1,2‐epoxy‐3‐(p‐nitrophenoxy)pro‐pane was only measurable in the livers and was inhibited 1 and 2 h after the administration of HgCl2and NaVO3. It is concluded that sublethal doses of CdCl2, HgCl2, or NaVO3do not impair the GSH concentration and GSH‐conjugating enzyme activities toward the aryl substrate in different target organs of their toxicity, which is in contrast to results obtained in vitro.