1. Chronic amphetamine administration (10 mg/kg) to young rats (Rattus norvegicus) (40-90 g) produced an initial hyperglycemia following the initial drug administration. This was followed by progressive hypoglycemia with the continuous drug treatment. 2. The present data also demonstrate increases in levels of serum ACTH and corticosterone that were maintained after drug withdrawal, in the case of corticosterone. 3. The Analysis of the transaminase activity revealed the occurrence of significant increases in serum GOT level. Furthermore, progressive increase in the G-6-Pase activity was recorded, reaching its maximum level by the end of the experiment, which demonstrates that induced amphetamine toxicity is time-dependent.