Methanol seed extract of Chrysophyllum albidum was studied to ascertain the potential effects of the extracts on some biochemical indices. The proximate composition of Chrysophyllum albidum seed methanol extract was found to contain crude protein (8.41± 0.02 mg/g), crude fat (19.12±0.01 mg/g), Ash content (1.42±0.01 mg/g) and moisture content (41.87± 0.03 mg/g). Results of the vitamin composition showed that it contains vitamin C (99.0± 0.03 µ/100g) vitamin A (70.0±0.01 µ/100g) and vitamin E (64.0± 0.03 µ/100g). The preliminary qualitative photochemical screening showed that the seed methanol extract of Chrysophyllum albidum contains flavonoids, alkaloids, resin, cardiac glycosides, saponins, terpenoids, steroid and tannins. The quantitative phytochemical analysis revealed the presence of flavonoids (1.54± 0.11 mg/100g), alkaloids (1.04± 0.04 mg/100g), glycoside (1.87± 0.02 mg/100g), saponins (3.66± 0.03 mg/100g), steroids (0.43± 0.01 mg/100g) and tannins (2.19±0.03 mg/100g). A total of thirty-six albino rats were assigned into nine (9) groups of four (4) rats each. The LD50 of the seed methanol extract of Chrysophyllum albidum was found to be less than 1000 mg/kg body weight. Groups 1, 2 and 3 represented normal, diabetic and standard control rats respectively. Groups 4, 5 and 6 represented diabetic rats treated with 100, 200 and 300 mg/kg b.w. of the extract respectively while Groups 7, 8 and 9 represented non-diabetic rats treated with 100, 200 and 300 mg/kg b.w. of the extract respectively. After induction of alloxan, the blood glucose levels of groups 2, 3, 4, 5 and 6 increased significantly (p< 0.05) compared to group 1 (normal control). After 5 days of treatment with the seed methanol extract, there was a significant (p<0.05) reduction in the glucose level of the diabetic treated except in group 3 and 5 compared to group 2 (positive control). There was no significant change (p>0.05) in groups 7, 8 and 9 (normal treated) when compared to negative control. Groups 3, 4, 5 and 6 (diabetic treated) showed no significant change when compared with a negative control after 5 days of treatment. Result of catalase activity showed a significant increase (p<0.05) in group 5 when compared to the positive control. There was no significant change (p>0.05) in catalase activity of rats in groups 3, 4, 6, 7, 8 and 9 when compared to positive control. Result of reduced glutathione (GSH) levels of rats in diabetic groups showed significant increase (p<0.05) compared to non-diabetic groups and the normal groups. The histopathology studies of liver and kidney of rats treated with the seed methanol extract showed that the extract was toxic.