The main toxic side effect of streptozotocin is on the kidney and the 8th cranial nerve, the nerve that transmits hearing and the equilibrium function of the inner ear. Kidney damage is the more common side effect and is related to the dose and total amount of the drug given. Careful monitoring of the urine analysis and blood test and blood tests for kidney function before each treatment, with aborting treatment if the starts of abnormalities are seen can prevent any significant renal damage. This should be done in all cases. Therefore, no patient need suffer side effects from this drug. Similarly, periodic audiograms and checks of the patients vestibular function will prevent irreversible 8th nerve damage. Monitoring blood counts and adjusting dosage or withholding the drug will avoid serious suppression of the white blood cells. Cardiac damage is not a regular complication of this drug and would be extraordinary.