Abstract: Objective To explore the toxic effect of methyl tertiary butyl ether in brain,liver,lung and kidney of rats.Methods 27 male SD rats were randomly divided into three groups,and then exposed in M TB E by intragastric administration,the doses of MTB E were M1:500 mg/(kg·bw),M2:1 500 mg/(kg·bw)(exposed)and M0:isovolumic normal saline(control)respectively.The drug were used once a day,for 4 weeks,then the rats were put to death,the LDH,GPT,GOT on blood serum,and the T-SOD,MDA,GSH on brain,liver,lung and kidney were measured;Light microscopes were also used to explore the possible damage of M TB E on these organs.Results Compared with the control group,the blood serum LDH of the exposed groups showed the downtrend,and the M2 group decreased significantly(P<0.05);the AL T of the exposed groups,compared with the control group,decreased significantly(P<0.05);the T-SOD levels in tissues of the exposed groups were lower than that of the control group,and the values were significantly lower(P<0.05)in the liver of M2 group,in the lung of M1 group and in the kidney of M1,M2 groups;the MDA levels were found no significant difference among the three groups;the exposed groups GSH showed the downtrend compared with the control group,and the GSH values in M2 group liver were significantly lower than that of the control group(P<0.05);Light microscopy analysis showed some pathomorphological changes in liver,lung and kidney.Conclusion M TB E might affect the levels of serum enzymes,damage both the free radical scavenging system,and the structure of normal tissue in liver,lung and kidney.