Treatment of diabetic mice with cyanidin-3-O-β-D-glucopyranoside extracted from mulberry fruit improves erectile function compared with diabetic mice that did not receive the treatment. The corporal tissues of the treated mice showed increased expression of nitric oxide synthase (NOS) and NOS protein and lower levels of apotosis. Adding to the evidence that the mulberry extract minimizes oxidative stress, treatment recovered the level of 8-hydroxy-2-deoxyguanosine in the diabetic mice to that of healthy mice.