The effects of ethanol and 4-methyl pyrazole were investigated in the treatment of 30 dogs toxicated with antifreeze (AF). The AF toxication produced significant increases in blood urea, creatinin and potassium and a decrease in blood calcium levels. Calcium-oxalate monohydrate, which is pathognomic for AF toxication, was consistently seen in urine sediment. Ethanol was rarely effective on the multisystemic effects that occurred in dogs or ADH inhibition. CNS findings were also observed after ethanol administration. The results indicated that 4-MP treatment provided earlier and safer healing than ethanol. It was deduced that 4-MP + NaHCO3 was more effective than ethanol + NaHCO3 on AF toxication, based on the metabolic parameters, urine chemistry and necropsy findings.