The plant, Bauhinia monandra Kurz, (Caesalpinaceae) is an ornamental. Traditionally, the leaves are used in the treatment of diabetes. 4.150 kg of the dried leaves of B. monandra was extracted with methanol (cold extraction), concentrated in vacuo to obtain 300 g of extract. Oral administration (p.o.) of the methanolic extract at 2 g/kg administered to alloxan-diabetic rats showed significant blood glucose reduction of 65% at the end of a 4 hour period similar to the effect of glibenclamide (5 mg/kg, p.o). The methanolic extract was successively partitioned into ethylacetate, butanol and water fractions, and the same test showed that the butanol fraction (2 g/kg) had 67.4 %, Water fraction had 71.5 % hypoglycaemic activity at 4 hours after oral administration comparable to that of glibenclamide (67.8 %) in the in vivo model. Subfractions of the butanol fraction (BMBuF7; 1 g/kg, BMBuF7C; 0.75 g/kg) reduced hyperglycaemia in alloxan-diabetic rats to 62 and 66 % respectively and induced insulin release from INS-1 cells. Quercetin-3-rutinoside was isolated from the butanol fraction and characterrized. The results justify the ethnomedical use of the plant in the management of diabetes and sugests that stimulating insulin release is one of the modes of action of the butanol fraction and some of its subfractions.