Abstract: Complications from diabetes mellitus demand for increase research on the disease. Forty eight Albino rats (randomly grouped into six) were used for the study. Diabetes was induced using 120 mg kg–1 b.wt., alloxan and different doses of the extract were administered orally for 40 days except in the diabetic untreated group. A weekly body weight measurement was also done. On day 40 fasting plasma glucose, total protein, albumin, urea, creatinine, aspartate aminotransferase (AST), alanine aminotransferase (ALT), malondialdehyde (MDA) and Total Antioxidant Capacity (TAC) were determined using standard methods. Results showed an initial weight loss in all the administered doses in the early weeks of extract administration and this improves as the effect of the extract became established in the later weeks. There was a 15.2, 7.4, 19, 11, 3.6 and 11.4% decrease, respectively in 200, 300, 500, 10000 mg kg–1 treated groups; normoglycemic and diabetic untreated group. Also, a non-significant (p>0.05) change in the plasma albumin, creatinine, urea, red blood cell and hemoglobin; a mixed significant change in plasma aspartate aminotransferase, alanine aminotransferase, total protein and globulin, a significant (p<0.05) decrease in plasma glucose and malondialdehyde and a significant increase in plasma total antioxidant capacity, white blood cells and lymphocytes were observed in the extract treated and normoglycemic control groups in comparison to the diabetic untreated group. Conclusively, ingestion of aqueous cocoa powder modifies the characteristic body weight changes, biochemical and hematological parameters in alloxan diabetes.