Ether extracts of Lythrum salicaria stems and flowers exhibited significant hypoglycemic activity in rats with glucose- and epinephrine-induced hyperglycemia when the animals were given oral doses equivalent to 10 g/kg of starting material. These extracts were also found to be active in alloxan- and streptozotocin-diabetic rats and alloxan-diabetic mice. While both stem and flower extracts reduced the elevated gamma-glutamyl transpeptidase activity induced by streptozotocin in rats, only the stem extract reduced the elevated lactic dehydrogenase activity also seen. The flower extract clearly accentuated the elevated levels of aspartate aminotransferase induced by streptozotocin.