Fibromyalgia is a common, chronic musculoskeletal disorder that is characterized by widespread pain and tenderness. Fibromyalgia occurs in around 2% of the US general population, is more common in women and is associated with substantial morbidity and disability. Treatment of fibromyalgia has been disappointing; roughly one-third of patients have had a clinically important therapeutic response to medications or no-medicinal treatment, event with the newest drugs reported in the literature. Pathophysiology of fibromyalgia is unknown, but abnormalities in central neurotransmission might play a role. Some studies have shown that salmon calcitonin increases peripheral and central levels of endorphins. Increasing endorphins levels may decrease pain. Then, it is feasible that nasal administered salmon calcitonin may decrease several of the symptoms and signs of patients suffering fibromyalgia.