Background: Diabetes mellitus and its complications are public health problems. Hyperglycemia triggers harmful biochemical effects to the body, such as oxidative stress and inflammatory process. The use of medicinal plants with high antioxidant capacity as Lepidium meyenii Walp (maca) is an alternative in treatment of this disease. Objective: To determine whether ingestion of maca flour improves the relation reduced/oxidized glutathione (GSH/GSSG) in diabetic rats. Design: Experimental. Setting: Biochemistry and Nutrition Research Center, Faculty of Medicine, Universidad Nacional Mayor de San Marcos, Lima, Peru. Biological material: Yellow maca flour and adult male Holtzman albino rats. Interventions: Diabetes was induced in 24 rats with streptozotocin (STZ) 40 mg/kg body mass; rats were randomly divided into four groups of six animals each: control (CO), glibenclamide (GL) 10 mg/kg body...