Diabetes is a serious public health problem worldwide. In Ecuador, diabetes is one of the first causes of human deaths. The community makes use of medicinal plants to treat diabetes, but without any scientific evaluation. Data about plants with antidiabetic activity were collected from oral surveys to herbalist retailers and consumers. Antidiabetic activity and acute toxicity were evaluated using Wistar rats (females) and OF1 (females) mice, respectively. The secondary metabolites and antioxidant capacity were quantitatively determined in plants with antidiabetic activity demonstrated in the preclinical study. The information obtained from oral surveys led to the identification of the medicinal plants that were mainly denominated as antidiabetics, the parts of the plants used and form of consumption for the treatment of diabetes. The plants Artemisia absintium, Cynara scolymus, Schkuhria pinnata, Chuquiraga jussieui y Taraxacum officinale were mostly nominated for the treatment of diabetes. However, only A. absinthium, C. scolymus and T. officinale presented antidiabetic activities and did not show preclinical acute toxicity in experimental animals at doses of 2000 mg/kg. This study shows that plants with antioxidant activities can be an effective therapy to prevent and fight chronic diseases such as diabetes.