The severity of pulmonary fibrosis cannot be determined by coughing up a lot of white sputum. The severity of the disease needs to be determined by combining the patient’s clinical symptoms, the presence of respiratory failure, imaging changes and pulmonary function tests. Patients with pulmonary fibrosis who cough up white sputum without shortness of breath, dyspnea, stable vital signs, no respiratory failure on blood gas analysis, and small lung involvement and normal lung function on imaging are generally not in serious condition. Patients with pulmonary fibrosis who have shortness of breath after activity, or even dyspnea during quiet time, with decreased oxygen saturation, and whose blood gas analysis suggests respiratory failure, as well as whose imaging reveals a large area of lung involvement and whose lung function shows severe restrictive ventilatory dysfunction and a severe decrease in diffusion volume, are more seriously ill. Patients with pulmonary fibrosis are advised to seek prompt medical attention to evaluate their condition and to take medications as prescribed to prevent disease progression.