Peripheral arterial disease is a common disorder effecting up to 15% of men over age 55 and women over age 65. Patients with peripheral arterial disease are at increased risk for stroke, myocardial infarction or other adverse vascular outcomes. Therapy for this disorder is currently limited with only 2 FDA approved drugs (Pentoxifylline, cilostazol). These agents improve walking distance by 10 to 40 percent. Other agents such as verapamil and prostacyclin analogs have significant side effects. Although therapy with angiogenesis inducers, including injections of plasmid constructs for vascular endothelial growth factor (VEGF) or VEGF protein, is beneficial, the widespread applicability of this therapy is questionable. The study used an alternative approach, which may be safer and more effective. The basis for this approach is the ability of L-arginine to enhance endogenous vascular nitric oxide production, improving blood flow acutely. Furthermore, since several angiogenic growth factors may act at least partially through the production of nitric oxide, this therapy could produce a sustained benefit by the induction of an increase in skeletal muscle capillary density.