This study was conducted to investigate the effects of Aralia elata, Acanthopanacis cortex and Ulmus davidiana water extracts on plasma glucose and biomarkers in the streptozotocin (STZ)-induced diabetic rats. Male Wistar rats were divided into normal and diabetic groups. The diabetic groups subdivided into the control group (DM), Aralia elata (DM-AE), Acanthopanacis cortex (DM-AC) and Ulmus davidiana (DM-UD). The extracts were supplemented in diet base on 11.42 g of raw materials/㎏ diet for 7 weeks. The diabetes was induced by injecting STZ (55 ㎎/㎏ B.W., i.p.) once 2 weeks before sacrifying. Plasma glucose level was significantly higher in the DM group than in the normal group, whereas insulin and C-peptide concentrations were significantly lowered in the DM groups compared to the normal group. These parameters were normalized in the DM-AE, DM-AC and DM-UD supplemented groups. Plasma albumin content was significantly lowered in the DM group compared to the normal group, yet it was significantly higher in the DM-AE group than in the DM group. Bilirubin and creatinine contents were elevated in the DM group, while the supplementation of Aralia elata, Acanthopanacis cortex and Ulmus davidiana water extracts ameliorate the change of these contents in STZ-induced diabetic rats. Plasma AST, ALT, ALP and LDH activities were significantly higher in the DM group than in the normal groups. The supplementation of Araliaceae family water extracts significantly lowered these parameters compared to the DM group. Accordingly, these results indicate that Aralia elata, Acanthopanacis cortex and Ulmus davidiana water extracts would seem to improve the glucose and biomarker in STZ-induced diabetic rats.