Idiopathic pulmonary fibrosis (IPF) is a rare lung disease that results in scarring (fibrosis) of the lungs due to an unknown reason. Over time, scar formation gets worse, making hard to take in deep breaths. IPF is a form of interstitial lung disease, primarily involving the interstitium (the tissue and space around the air sacs of the lungs), and not directly affecting the airways or blood vessels. There is no cure for IPF and there are currently no procedures or medications to remove the scarring from the lungs.