The statement that spitting white phlegm can kill you is not scientific. Spitting white phlegm is usually caused by chronic pharyngitis, acute bronchitis and other diseases, which will not kill you. However, spitting white sputum caused by lung cancer and heart failure may kill you. 1. Chronic pharyngitis: If there is a small amount of white sputum, not accompanied by other systemic symptoms, or only mild symptoms such as foreign body sensation in the pharynx and irritating cough, then chronic pharyngitis is more likely. 2. Acute bronchitis: patients with acute bronchitis may cough and cough up white sputum, which is usually caused by pathogenic microorganisms such as virus, bacteria or mycoplasma infection. 3. Lung cancer: patients with advanced stage of lung cancer who are accompanied by obvious fatigue, shortness of breath and spitting white sputum that is sticky. Patients may have obvious weakness in coughing up sputum and sputum clots, which may lead to respiratory failure and suffocation. 4. Heart failure: heart failure coughing and spitting white sputum may be caused by pulmonary edema, this sputum is usually thin white foamy sputum or pink foamy sputum, the patient will also be accompanied by tightness in the chest, shortness of breath, sweating, and untimely treatment may be life-threatening. There are many reasons for white sputum, which cannot be generalized, and patients should go to the hospital in time for proper treatment under the guidance of the doctor.