Pirfenidone is useful in the treatment of pulmonary fibrosis. Pulmonary fibrosis is an interstitial lung lesion. When pulmonary fibrosis is present, treatment with anti-pulmonary fibrosis medicines is useful in controlling the condition and preventing progression. For example, drugs such as pirfenidone can be used to treat pulmonary fibrosis, belonging to the anti-pulmonary fibrosis drugs. It is important to note that pulmonary fibrosis is difficult to reverse, and the use of pirfenidone may help to slow the progression of the disease, but generally does not cure pulmonary fibrosis. Pirfenidone may cause adverse reactions such as photosensitivity, gastrointestinal reactions, tachycardia, and drowsiness. Therefore, patients with pulmonary fibrosis may consider using pirfenidone, but they need to use the drug appropriately under the guidance of a doctor and need to be monitored for adverse drug reactions.