Nitric oxide (NO) has attracted the attention of many researchers due to its multifunctional role in human biology. Its diverse actions have not spared the skin. NO is endogenously produced in the skin. Additionally, the skin is capable of rapidly releasing NO upon exposure to ultraviolet A in an enzyme independent manner.Preformed photolysable nitrosospecies stores in the skin are important sources by which UVA can generate NO non-enzymatically. We hypothesized that the superficial dermal vasculature could contribute nitrosospecies to this store.Our results indicate that circulating nitrosospecies serve as a reservoir for the cutaneous store. Dietary derived nitroso compounds could increase the cutaneous stores of NO via the circulation. Next we were interested in knowing whether the NO produced by this photolysis mechanism cause photorelaxation of blood vessels and reduce blood pressure in humans.Ultraviolet A seems to cause a change in circulatory nitrosospecies. Lastly we studied the role of NO in the pathophysiology of the common skin disease psoriasis. Our work has confirmed the pivotal role of cutaneous NO in man and has opened the doors for further studies in this field.