Diabetes mellitus is a major public health problem in the world. The prevalence ofrndiabetes mellitus is increasing with ageing of the population and lifestyle changesrnassociated with rapid urbanization and westernization. According to the WorldrnHealth Organization estimate 3% of the worldâ€™s populations (194 million) haverndiabetes and is expected to double (6.3%) by the year 2025 and that of Ethiopia wasrnabout 800,000 cases in 2000, and the number is expected to increase to 1.8 millionrnby 2030.rnStevia rebaudiana Bertoni (Asteraceae) and Ajuga remota Benth (Lamiaceae) hasrnbeen used for the treatment of diabetes mellitus and various other ailments in therntraditional medical system world wide. This study reports the antidiabetic activity ofrncrude extracts of Stevia rebaudiana Bertoni & Ajuga remota Benth grown in Ethiopiarnon alloxan-induced diabetic micernA preliminary toxicity study of S. rebaudiana and A. remota crude extracts was donernusing Swiss albino mice in oral doses of 1000, 2000 and 5000 mg/kg body weight.rnThe result showed that the medium lethal dose (LD50) of the extracts is higher thanrn5000 mg/kg body weight and hence, in a single dose administration, the plantrnextracts had no adverse effect. The result obtained is in agreement with that ofrnGeuns (2003) for S. rebaudiana and Worku (2005) for A. remota.rnThe preliminary phytochemical screening indicated the presence of flavonoids,rnsaponins, tannins and steroids in both plants and alkaloids in the leaves of S.rnrebaudiana.rnExtracts of both plants did not contain anthraquinones. The resultrnobtained here is in agreement with that of Anonymous-a (1999) for S. rebaudianarnand Worku (2005) for A. remota.rnA concentration of 2.27 % stevioside was obtained in the leaves of S. rebaudiana.rnThe antihyperglycemic activity of the crude aqueous and ethanol extracts of S.rnrebaudiana and A. remota were studied in alloxan-induced (200 mg/kg body weight,rnip.) diabetic mice, after oral administration at a dose of 300 and 500 mg/kg bodyrnweight for two weeks. Administration of crude aqueous extract of S. rebaudiana forrn14 days lowered elevated blood glucose levels by 30.27% (300 mg/kg) and 42.65%rn(500 mg/kg) that shows S. rebaudiana has retained its antidiabetic activity whenrngrown out of its natural habitat, i.e. in Ethiopia. In the case of A. remota, bloodrnglucose reduction was 27.96% and 38.98% respectively for the dose levels tested.rnCrude ethanol extract of S. rebaudiana and A. remota (300 and 500 mg/kg bodyrnweight for 14 days) lowered blood glucose level by 28.71% & 33.04% and 28.09% &rn28.25% respectively as compared with diabetic untreated mice. Treatment with thernknown antidiabetic drug, glibenclamide (10 mg/kg body weight) lowered bloodrnglucose level by 51.06%. The effect was more pronounced in the case of the crudernaqueous extract as compared with the crude ethanol extract on the respective dosernlimits for both plant cases.rnKey words: Diabetes mellitus, Stevia rebaudiana, Ajuga remota, SteviosidernAntidiabetic activities, Blood glucose level