The fruit extract of Momordica charantia Linn. was studied in Charles Foster rats of both sexes in respect of its dose-response hypoglycemia and at maximal effective dose, its influence on the development of diabetic cataract. Alloxan (120 mg/kg s.c./rat, single dose) diabetic rats with greater than 150 mg% of blood sugar were classified into four groups (n = 10) wherein two were control and the rest were test groups). In the test group, the oral dose response hypoglycemic herbal effect was found to be maximum at 4 g/kg/Day/rat when administered for 20 days. This dose was continued in the 2nd test group for a period of 2 months. Blood sugar in all the rats was estimated by microdetermination method using a dextrometer before and after therapy. The control group of rats received 2 ml of 0.9% NaCl and they developed cataract in 90 to 100 days. The herbal treated diabetics showed cataract in 140 to 180 days. Cataract formation was found to be dependant on blood sugar levels since the control group with blood sugar 307 +/- 81 (mg%) was blind 2 months earlier than herbal treated group which showed blood sugar 149 +/- 66.37 (mg%).