The effects of crude powder of Ganoderma spp. on blood glucose, average body weight and some hematological parameters were investigated in Wistar rats. Qualitative phytochemical screening of the crude powder revealed the presence of carbohydrates, tannin, cardiac glycosides, saponin glycoside, terpenoid and flavonoids. Acute toxicity study with 5 g of crude powder of Ganoderma lucidum in 20g of feed was evaluated using the up and down method. No mortality was observed after 24 hours of observation. 30 Wistar rats were used for this study; they were randomly grouped into five groups (A, B, C, D and E) with 5 rats in each group. Groups A, B, C and D were used as the experimental group and were orally administered with graded doses of 200 mg/kg, 400 mg/kg, 800 mg/kg and 1600 mg/kg respectively of Ganoderma lucidum powder mixed with 5000 mg/kg of feed for four consecutive days, while group E was used as the control group and was administered with non Ganoderma lucidum impregnated feed and clean drinking water provided ad libitum for four consecutive days. The powder exhibited decreases in Wistar rat’s body weight, blood glucose profile. Haematological study showed decreases in red blood cells, haemoglobin concentration and packed cell volume, while there was no Significant change in white blood cell count. These findings revealed hypoglycemic effects and weight reducing potentials of this Ganoderma spp, and relating to its possible use in the management of diseases such as diabetes mellitus and obesity