Pulmonary fibrotic foci are fibrous lesions caused by the proliferation of fibroblasts in the lungs. If the fibrotic foci are large enough to cause the lungs to function abnormally, they need to be treated aggressively. Infections of the lungs, especially bacterial or viral infections or autoimmune diseases, may lead to the proliferation of fibroblasts in the lungs and repair of lung damage, resulting in the development of pulmonary fibrotic foci. Fibrotic changes in the lungs may lead to thickening of the interstitium and destruction of the lung structure, which may result in decreased or loss of lung function or ventilation. At this time, patients need to actively treat the primary disease with antibiotics and antiviral drugs along with antifibrotic treatment with medications, and hormones such as prednisone can be used for treatment if necessary. If pulmonary fibrotic foci appear, you should seek medical treatment in time, do not self-medication.