Objective: To investigate the effect of administration of Passiflora glandulosa (P. glandulosa) fruit rinds flour on streptozotocin (STZ)-induced diabetic mice. Methods: The preliminary phytochemical screening and parameters such as centesimal composition and brine shrimp toxicity were evaluated. For in vivo study Swiss female mice were divided into four groups: NC-normal control; DC-diabetic control animals receiving saline; MET-diabetic animals receiving metformin (200 mg/kg); PFRF-diabetic animals receiving P. glandulosa fruit rinds flour (200 mg/kg). All of them were treated for 28 d. STZ was used in a single dose of 120 mg/kg to establish diabetic models. Body weight, water and food intake, fasting blood glucose were measured. Histopathological analysis of pancreas and liver were performed to evaluate STZ-induced tissue injuries. Results: Phytochemical screening showed the presence of flavanones and triterpenoids. The P. glandulosa fruit rinds flour was non-toxic by the brine shrimp test. The fruit rinds flour also reduced the loss of body weight and significantly decreased food intake in the diabetic mice. Additionally, a significant reduction in blood glucose was observed for 15 d and this was maintained on 21 d and 28 d when compared with diabetic mice. Furthermore, the P. glandulosa fruit rinds flour has a favourable effect on the histopathological changes of the pancreas in STZ induced diabetes. Conclusions: It is concluded that P. glandulosa fruit rinds flour is a natural product that contains potent antioxidant compounds and presents good prospects for the improvement of diabetic mellitus by reducing serum glucose levels.