Objective: To evaluate the antidiabetic and the antidiarrhoeal effects of ethanolic extracts of Psidium guajava leave (EEPGL) in Wister rats to support its traditional uses. Methods: Oral glucose tolerance test model and alloxan induced diabetic test model were performed to evaluate antidiabetic activity of EEPGL at doses of 1.00, 0.50 and 0.75 g/kg respectively. For antidiarrhoeal effects of EEPGL, castor oil-induced diarrhoea model and gastrointestinal motility test with barium sulphate milk model were also assessed at doses of 750, 500 and 250 mg/kg, respectively. Results: Administration of EEPGL at doses 1.00 and 0.50 g/kg significantly (P<0.05) decreased blood glucose levels in oral glucose tolerance test model as well as 0.75 g/kg dose in alloxan induced diabetic test model in Wister rats (P<0.001). Application of EEPGL at doses of 750 and 500 mg/kg showed antidiarrhoeal effect in castor oil-induced diarrhoeal model (P<0.001 and P<0.01, respectively), and 750 mg/kg (P<0.01), 500 and 250 mg/kg (P<0.05) doses in barium sulphate milk model in aforesaid animals. Conclusions: These results exhibited the significant antidiabetic and antidiarrhoeal activities of ethanolic extracts of Psidium guajava leave in Wister rats