Diabetes mellitus (DM) is a serious global public health problem. DM complications corroborate with high morbidity and mortality rates. Thus, several plant species have been studied regarding their medicinal properties with potential use in the treatment of DM and/or its complications. This study evaluated the effects of leaf (LE-OPN) and bark (BE-OPN) extracts from ora-pro-nóbis (Pereskia aculeata) on biochemical parameters (glycemia, triglycerides, total cholesterol, creatine, urea, AST and ALT, and lipid peroxidation) and histology (heart, liver and kidneys) in animals with DM. Induction of type 1 DM (glycemia > 200 mg/dl) in male Wistar rats was performed with Alloxane (150 mg/kg/ml). The animals were divided into 4 groups: (1) without DM, (2) with DM, (3) with DM treated with LE-OPN and (4) with DM treated with BE-OPN. The treatment was done by gavage (300 mg/kg/day) for 4 weeks. After this period the parameters were evaluated. BE-OPN prevented the increase in triglycerides, AST, ALT, and urea, in addition to lipid peroxidation (p < 0.05). The results suggest a potential for BE-OPN to prevent typical complications of DM, improving the lipid profile, liver, and kidney, as well as attenuating oxidative stress.