Abstract: The alkaloidal composition, histopathological and toxicity studies of alkaloid and aqueous ethanol extracts of Boscia angustifolia on biochemical indices of kidney and liver functions in rats were studied. The amount of alkaloids detected in 50 g powdered root extract of the plant was 11.44% (w/v). Renal and liver indices were significantly (p<0.05) altered at higher doses of 703.60, 1125.70 (alkaloidal extract), 839.30 and 1342.80 mg kg-1 body weight (aqueous ethanol extract). The aqueous ethanol and alkaloidal root extracts produced histopathological lesions of the liver and kidney at higher doses. These lesions include perivascular cuffs, protein cast, infiltration (kidney) and slight infiltration and perivascular cuffs (liver). There was a significant (p<0.05) dose dependent decrease in weight in the rats given higher doses of the aqueous ethanol and alkaloidal root extracts of Boscia angustifolia. The use of this plant is associated with some levels of organ toxicity.