There are many reasons for spitting yellow sputum, and common causes include upper respiratory tract infections, pneumonia and tuberculosis with bacterial infection.
1. Upper respiratory tract infection: Upper respiratory tract infection is common in viral infection, often white sputum, if it is caused by bacteria, such as staphylococcus aureus infection, sputum will be yellow sputum.
2. Pneumonia: Bacterial pneumonia, due to inflammation of the lungs, increasing secretions in the lungs, coughing up sputum with necrotic material and bacteria, yellow sputum can occur.
3. Tuberculosis with bacterial infection: non-purulent chronic inflammation caused by Mycobacterium tuberculosis infection, usually coughing up white mucus sputum, if accompanied by bacterial infection will also spit yellow sputum.
Spitting yellow sputum may have other causes, such as lung abscess, lung tumors, etc., so you should go to the hospital in a timely manner, the doctor according to the specific conditions and auxiliary examination to determine the cause of the disease.