The acute hypoglycaemic effect of water and ethanolic extracts of three Viscum album subspecies, ssp. album, ssp. austriacum, ssp. abietis, were investigated in normoglycaemic and streptozotozocin-induced diabetic rats. Blood glucose level was measured according to glucose oxidase method. The antioxidant activity of these extracts was also studied in the liver, kidney and heart tissues of streptozotocin-induced diabetic rats after subacute administration. In order to determine antioxidant activity of extracts, tissue MDA and GSH levels were measured by using spectrophotometric methods. All results were compared with the diabetic control groups. The findings obtained in the experiments demonstrated that European mistletoe (Viscum album L.) subspecies possess potent antihyperglycaemic and antioxidant activity depending on host plant. (c) 2005 Elsevier Ireland Ltd. All rights reserved.