Context: Several therapeutic effects such as antioxidant and blood glucose-lowering activities have been reported for Peganum harmala L (Zygophyllaceae) (PH) seeds, Rhus coriaria L (Anacardiaceae) (RC) fruits, and Urtica dioica L (Urticaceae) (UD) leaves.Objective: This study investigates the effects of a triplex mixture (1:1:1) of these medicinal plants on metabolic and histological parameters in diabetic rats.Materials and methods: Aqueous extracts of PH, RC and UD were administered as either monotherapy or in combination at a final dose of 200 mg/kg to alloxan-induced diabetic rats by daily gavage. Biochemical parameters including blood glucose, liver function-related enzymes, lipid profile, and creatinine were estimated by spectrophotometric methods. Tissues from the liver and kidney stained with hematoxylin/eosin were histologically examined. The results obtained from the exposure groups were compared to either healthy or diabetic control groups.Results: Compared with the diabetic control rats, all aqueous extracts (ED50 = 11.5 ± 2.57 mg/ml) led to significant decreases in the levels of ALP (1.39–2.23-fold, p < 0.05), low-density lipoprotein cholesterol (LDL-C) (1.79–3.26-fold, p < 0.05), and blood glucose (1.27–4.16-fold, p < 0.05). The serum concentrations of TG was decreased only by treatment with UD and triplex mixture (1.25- and 1.20-fold, respectively, p < 0.05). Among the studied parameters, alanine aminotransferase (ALT), LDL-C, TG, and creatinine recovered to healthy control levels after 4 weeks of treatment with the extract mixture.Conclusion: This study showed that PH, RC, and UD extracts, especially their combination, had significant antidiabetic, hypolipidemic, and liver and renal damage recovering effects.