Abstract: Objective To Study the effects of exogenous cadmium-metallothionein(CdMT)on the distribution of cadmium in cell and its correlationship with cytotoxicity.Methods BALB/c mice were administered with the purified CdMT and A po-MT daily for 4 weeks as tested objects.Cadmium in ery throcyte(RBC-Cd)and splenic lymphocyte(sLC-Cd),as well as the cytotoxic indexes of splenicly mphocyte were detected.And the correlationship between each index was analyzed.Results RBC-Cd and sLC-Cd were increased significantly in groups treated with various dose of CdMT.There were obvious suppression of Tlymphocyte proliferation,changes of T-subsets and increasement of DNA single strands breaks(DNA-SSBs).Conclusion There were Cd²⁺ absorption in erythrocyte and redistribution in splenic lymphocyte of tr eated mice,which correlated with its immune suppression and the DNA damage after administered with CdMT via gastrointestine.