Effects of powdered Mucuna pruriens seeds on blood glucose levels were investigated in normal and alloxan-diabetic rabbits. In normal group 0.5, 1 and 2 g/kg of M. pruriens pulv significantly decreased the blood glucose levels while in alloxan-diabetic rabbits only 1 and 2 g/kg body weight caused a significant fall. The reference drug, acetohexamide in 500 mg/kg dose significantly reduced the blood glucose levels but in normal rabbits only. High levels of trace elements like manganese, zinc, and others were found in these seeds. Therefore, it is conceivable that M. pruriens seeds contain hypoglycaemic principles, may be both organic and mineral, which seem to act indirectly by stimulating the release of insulin and/or by a direct insulin-like action.