Obstructive Sleep Apnea (OSA) is the most common sleep disorder affecting up to 9-24 % of middle aged adults, and is becoming increasingly implicated in the pathogenesis of hypertension, and other cardiovascular disorders. Up to half of patients with OSA have hypertension, and their risk of developing hypertension increases with the increasing severity of Sleep Apnea. Patients with OSA and no hypertension have endothelial dysfunction, which is believed to be the precursor for most cardiovascular disorders. The upper airway collapse, and obstruction that occur in OSA result in a pattern of intermittent hypoxia, that has been shown to be the cause of the hypertension, and endothelial dysfunction found in patients with OSA. Intermittent hypoxia results in oxidative stress, which in turn is linked to the pathogenesis of hypertension and endothelial dysfunction. This protocol evaluates the role of the oxidative stress in endothelial function and blood pressure in patients with OSA. This is a pilot clinical study that will compare oxidative stress parameters, and endothelial function in patients with OSA before and after a two week course of the either one of the antioxidant drugs Allopurinol, and vitamin C. A skin biopsy of the forearm will be done to isolate dermal arterioles, and vascular endothelial cells at baseline and again following the 2 week period. This will enable assessment of the endothelial function. Oxidative stress parameters will be assessed in the plasma by blood draw. The two drugs are widely used with a very reasonable safety profile, specifically for a limited two week course. The skin biopsy is a minimally invasive procedure. Obtaining vascular tissue with the skin biopsy is a pioneering technique that has already lead to significant findings in the field of vascular biology. The area of cardiovascular complications of sleep apnea is in great need for research to understand the mechanisms of the interaction, and provide therapeutic options to a segment of the population exceeding 24% of men, and 9 % of women. Great attention is given to this area by public and governmental organizations such as the NIH.