Examination of the subacute toxicity of captafol showed that. 1) In the captafol administered group, the body weight was significantly decreased but the amounts of AST, ALT, LDH, BUN, TG in serum were remarkably elevated in comparision to those of the control group. 2) In captafol treated animals, the amount of cytochrome P-450 and the activity of NADPH-cytochrome c reductase in liver and in kidney were decreased, but TAB value in serum and in liver and total ATPase activity in liver and in kideny were found to be remakably elevated. 3) When captafol administered with ethanol to the group, the group showed elevated serum levels of AST, ALT and BUN but the amount of cytochrome P-450 and the activity of NADPH-cytochrome c reductase in liver and in kidney were decreased as the group which was treated with captafol only.