In this work the mechanism of the hypoglycemic effect of an aqueous extract from Cleome droserifolia (SAMWA) was studied in a group of glucose intolerant senile rats and compared with normal senile control rats. The plant extract significantly suppressed the rise in blood glucose concentration. The hypoglycemic effect of the plant extract without increasing insulin secretion was explained by: 1) potentiation of peripheral and hepatic insulin sensitivity, 2) by diminishing intestinal glucose absorption, which was evident by blunting plasma glucose levels throughout the oral glucose challenge. This was accompanied by a significant decrease of liver glycogen content and a highly significant increase in leptin concentration which may suggest an anti-obesity role for the plant extracts. Plant extracts also decreased serum urea nitrogen. No changes on liver or heart function were observed. In histological sections of liver and kidney minor changes were noticed. These extracts might prove to have a promising therapeutic value in the treatment of diabetes mellitus. Besides its suppression to hepatic glucose output, SAMWA beneficial therapeutic finding in favor of the plant as a replacement for insulin which is the most important drug that brings bout this effect.