Since the 18th century tuberculosis has been a major cause of death throughout the world. It is a highly infectious disease that spreads by droplet infection and finding effective treatment to combat tuberculosis took a great deal of time. One of the first treatments to have some real success was a stay in a sanatorium. Sanatoria were homes that provided patients with good food and fresh air (and therefore sunlight). The first sanatorium to use sunlight therapy (heliotherapy) seriously was founded in Leysin, Switzerland, by Auguste Rollier. Patients built up their sun exposure gradually to prevent sunburn or skin damage. We suggest that heliotherapy was more successful in treating tuberculosis than was appreciated once chemotherapy became available. The birth of heliotherapy coincided with an increased appreciation of the association of sunlight and health among the general public. The secret of its success is the combined effects of sunlight on the skin inducing the production of nitric oxide and vitamin D. Nitric oxide is not only a messenger in the cardiovascular system and responsible for relaxation of vascular muscle but is also involved in the innate immune system. Vitamin D is responsible for immune system functions and multiple studies have found an association between tuberculosis immunity and high vitamin D levels. Therefore, it is understandable that providing tuberculosis patients with sunlight may have boosted their immune system and aided them in the fight against tuberculosis. In view of the high level of resistance to all drug regimens in some patients, perhaps it is time to revive the use of sanatoria in the fight against tuberculosis.
