The purpose of the present investigation was to assess the pharmacological properties of Tournefortia hartwegiana Steud (Boraginaceae), used in traditional medicine for the treatment of diabetes, diarrhea and kidney pain in Morelos, Mexico. Administration of methanol extract from aerial parts of Tournefortia hartwegiana (310 mg/kg body weight/day) for 10 days, to normoglycemic and alloxan-induced diabetic rats, significantly lowered their blood glucose levels (37 and 36%, respectively, p<0.05). The anti-diabetic and hypoglycemic activities due to the MeOH extract were similar to those produced by metformin at 120 mg/kg (positive control, p<0.05). In contrast, the hexane, dichloromethane and MeOH extracts from the same species showed no significant spasmolytic effect and did not have activity in antibacterial and Artemia salina toxicity bioassays.