Idiopathic pulmonary fibrosis (IPF) is a diffuse lung disease, associated with the histological appearance of usual interstitial pneumonia (UIP), with an inexorably deteriorating clinical course. Prognosis is poor, reported median survival is less than 3 years. The prevalence is estimated as being 3 to 10 per 100.000 in different Western populations. To date, no pharmacological therapy has been proven to alter or reverse the pathogenic process of IPF. Most treatments trials have been observational case series of small patient populations and very few have been randomized, prospective and placebo-controlled.