In this work the mechanism of the hypoglycemic effect of the plant Cleome-Droserifolia (C.d.) was studied in a group of albino rats rendered glucose intolerant by tetracycline (T.) induced fatty liver, and compared with a normal control (C.) rats. The plant extract significantly suppressed the rise in peripheral blood glucose concentrations, both in the basal (fasting) state and after glucose intake. Suppression of basal blood glucose indicated a lowering effect of the plant extract on hepatic glucose output (HGO). The postprandial hypoglycemic effect of the plant extract without increasing insulin secretion was explained by; First: Potentiation of peripheral and hepatic insulin sensitivity. Second: by diminishing intestinal glucose absorption, which was evident by blunting plasma glucose levels throughout the oral glucose challenge. This plant might prove to have a promising therapeutic value in the treatment of diabetes mellitus, for besides its postprandial hypoglycemic effect, its suppression to hepatic glucose output in the fasting state is a beneficial therapeutic finding in favour of the plant as insulin is the most important drug that brings about this effect. The plant has also got a hypocholesterolemic effect more specifically on low density lipoprotein cholesterol (LDL-C) which consequently raised the high density lipoprotein cholesterol/low density lipoprotein cholesterol (HDL-C/LDL-C) ratio. This adds to its value as a protective and antiatherogenic agent.