Few foci of fibrosis in the lungs are caused by scarring due to related injury to the lungs. More commonly, inflammation damages the lungs and fibrosis forms when a large number of fibroblasts proliferate in the lungs. If there is a large amount of fibrosis, it can lead to impaired lung function and breathing difficulties. If it is a small amount of fibrosis, it has no effect on lung function and does not cause symptoms related to coughing, coughing, chest pain, etc. Clinically fibrosis is also strongly related to long-term smoking, environmental factors, etc. It is necessary to exclude and prevent related precipitating causes, and its can stop further fibrosis. For fibrosis that has formed, regular chest CT should be performed to determine its changes.