Abstract Fenugreek (Trifolium foenum graecum) a leguminous herb, is extensively cultivated in India, Mediterranean region and North Africa. It is used for culinary and medicinal purposes and also for fodder in various parts of the world. The hypoglycemic effect of fenugreek seeds and leaves was tested in normal and diabetic subjects. Six protocols A, B, C, D, E and F involved the acute administration (single dose of 25 g of seeds, 5 g of gum isolate and 150 g of leaves) of whole fenugreek seeds, defatted fenugreek seeds, gum isolate, degummed fenugreek seeds, cooked fenugreek seeds and cooked fenugreek leaves to healthy subjects. The rise in plasma glucose after a dose of glucose or meal was prevented by fenugreek seeds. The serum insulin levels were also modified (P<0.05). The reduction in area under glucose curve was greatest with whole seeds (42.4%), followed by gum isolate (37.5%), extracted seeds (36.9%), and cooked seeds (35.1%) in that order. The degummed seeds and fenugreek leaves showed little effect on glycemia. Fenugreek seeds were also administered for 21 days to diabetic subjects. A significant imporvement in plasma glucose and insulin responses was observed in these subjects. The 24 hr urinary glucose output and serum cholesterol levels were also reduced (P<0.05).