Hyperglycaemia-induced oxidative stress plays a crucial role in the development and progression of diabetes mellitus (DM). Albeit, insulin has remained an important component treatment plan for DM management in patients with type 1 diabetes mellitus (T1DM), it fails to prevent the long-term complications. Experiment aimed at investigating ameliorative effects of probiotic and vitamin C (vit-C) treatments on the hyperglycaemia and oxidative stress in alloxan-induced diabetic rats. Wistar rats (male, 100-180g, n=48) were allowed to acclimatize for two weeks, animal experiments adhered to the Guide for the Care and Use of Laboratory Animals (NRC, 2011). T1DM was induced in overnight-fasted rats by a single i.p. injection of alloxan (150 mg/kg, dissolved in a cold physiological saline (0.9 % NaCl) solution. Blood glucose (BG) concentration of the rats was measured 72 h after alloxan administration. BG concentration in all groups were recorded following 12-h fast each day at 8:00 AM before feeding the rats using glucometer (On Call®Plus, 30175, Germany), and glucose test strips. Animals with BG concentration ≥14 mmol/L were considered diabetic (Lenzen, 2008). At the end of the experiment, rats fasted overnight were killed by jugular venisection after light chloroform anaesthesia. 5ml of blood from each rat collected into dried tubes and centrifuged at 2000 × g for 15 min to obtain serum. Activities of catalase and glutathione peroxidase were determined spectrophotomerically, according to Beers and Sizer (1952), Paglia and Valentine (1967), respectively using the serum and tissues homogenates. Malondialdehyde concentration in serum and tissues of rats was determined, according to Placer et al. (1996). Six groups of animals (n=8, per group) received the following treatment regimens for 4 weeks: 1) Oral administration of normal saline; 2) alloxan (150 mg/kg, i.p.); 3) alloxan (150 mg/kg) + insulin (4 U/kg, s.c.); 4) alloxan (150 mg/kg) + probiotic (4.125 × 106 CFU/100 ml per os); 5) alloxan (150 mg/kg) + vit-C (100 mg/kg, i.m.); 6) alloxan (150 mg/kg) + probiotic ( 4.125 × 106 CFU/100 ml per os) + vit-C (100 mg/kg, i.m.). Experiment lasts 4 weeks. Values are means ± S.E.M., compared by repeated-measures ANOVA. Decrease in BG concentration (12.55±0.89, P<0.001; 13.03±0.74, P<0.001; 11.02±0.69, P<0.001; 10.97±0.76 mmol/L, P<0.001) was obtained in diabetic treated groups compared to control. Treatment with probiotic + vit-C decreased BG concentration (10.97 ± 0.76 mmol/L, P < 0.01) than the untreated diabetic group (14.18 ± 0.68 mmol/L). Probiotic + vit-C, reduced lipid peroxidation in the serum, brain and kidney (Figures 1, 2, and 3, respectively) but increased activities of antioxidant enzymes. In conclusion, probiotic + vit-C may be effective in ameliorating hyperglycaemia, and oxidative stress in alloxan-induced diabetic rats.