Streptozotocin (2deoxy-2-(3. methyl3nitrosourea) ldglucopyranose)(ol t/3) is an antibiotic isolated in 1959 from Streptomyces achromogenes var.~ tre~ tuzotic~ s found in a soil sample collected at Blue Rapids, Kansas. The wide range of biological effects of this material were discussed as follows: history, diabetogenesis and the underlying mechanisms, tumorigenesis, clinical applications. The complete structural detestation was reported in 1979 althou~ chemical synthesis was accomplished as early as 1967. WeIl over a hundred analogues are actually known. In the natural state, streptozotocin exists as a 50-50 mixture of (Y and 0 anomers. In about one third of the analogues, the basic streptozotoc~ structure has been retained but modifications include acetylations, alkylations, replacement of the nitroso group. The acetyl derivatives are as active as the parent molecule. The alkyl glycoside analogues exhibit substantially reduced antibacterial property but retain antitumour activity. Replacement of the methyl group by 2-chloroethyl results in chlorzotocin that seems superior to streptozotocin as a clinically useful anti-tumour agent. The usefulness of other chemical modifications is less certam (Wiley). un tin t-0 t-0