Idiopathic Pulmonary Fibrosis: is a type of lung disease that results in scarring (fibrosis) of the lungs for an unknown reason. Over time, the scarring gets worse and it becomes hard to take in a deep breath, as a result the lungs cannot take in enough oxygen. Lung tissue becomes scarred and changes the lung's ability to function normally. The scarring typically starts on the outside edges of the lungs and eventually advances towards the center of the lungs. IPF is a disabling disease without a known cure.