There are many reasons for coughing up white foamy sputum, such as bronchitis, lung cancer, and cardiac insufficiency. When bronchitis is caused by virus, mycoplasma, chlamydia, etc., the symptoms of coughing and coughing white foamy sputum will appear. A few lung cancers, such as mucinous lung cancer, can cause a large amount of white foamy sputum, which can be coughed up to one hundred or even several hundred milliliters of white foamy sputum per day. In addition to lung disease, it can also be caused by heart disease. Patients with heart failure may have increased pulmonary venous pressure due to pulmonary stasis, resulting in varying degrees of pulmonary edema and hence white foamy sputum. White foamy sputum may also be caused by other diseases, such as tuberculosis, pneumonia, pharyngolaryngitis, chronic obstructive pulmonary disease, and it is recommended that the patient consult a doctor in time and follow medical advice.