Abstract: The effects of cassava cyanide on the antioxidant (glutathione) status and some clinically important enzymes were investigated biochemically in male albino wistar rats fed for 28 days with cassava diet containing 54.6 mg CN_kg-1 DM and 10% protein supplement. Analysis of the urinary and serum cyanide and thiocyanate of the test and control rats showed a statistically significant difference (p<0.05) between the test and the control. The mean serum and urinary cyanide were 2.92±0.53 and 8.21±6.32 μg mL-1 after 7 days and 3.80±0.67 and 11.08±0.54 μg mL-1 after 28 days, respectively. Mean serum and urinary thiocyanate were 16.73±0.42 and 19.90±1.35 μg mL-1 after 7 days and 18.14±0.18 and 36.59±1.87 μg mL-1after 28 days, respectively. Depletion in whole blood glutathione level by 47.3 and 89% (after 7 and 28 days, respectively) compared to that of the control was also observed. Increases in plasma activity of aspartate aminotrasferase (90%), alanine aminotrasferase (88.5%) and alkaline phosphatse (49%) were also measured after 28 days of the feeding experiment. There was elevation in blood glucose of the test animals, while the levels of protein and albumin remain within the normal range for both test and control animals.