Turnera diffusa (damiana) grows wild in Baja California Sur (BCS), Mexico. It is traditionally used for its aphrodisiac effects and for diabetes treatment. Two varieties (var.) have been identified: diffusa and aphrodisiaca. To evaluate the effects of water-ethanol extracts from both varieties, measurements on blood glucose, body weight, biochemical parameters, and cell blood counts were performed in a diabetic rat model. Oxidative stress was also evaluated when var. diffusa was administered. No significant reductions in blood glucose levels, in biochemical parameters, or in cell blood counts with any variety of damiana were observed; however, it helped diabetic animals to keep their body weight. Damiana var. diffusa did not modify the mitochondrial nitric oxide levels and superoxide dismutase activity; however, thiobarbituric acid reactive species diminished. In conclusion, damiana can be utilized reliably in the management of diabetes because of its antioxidant potential; it promoted body weight loss in healthy animals and helped to preserve it in diabetes.