The difference between white sputum and yellow sputum is that they can be different colors caused by different diseases, or they can be seen at different times in the same disease. Different colors are caused by different diseases: white sputum tends to appear in patients with fungal infections, and the sputum is often white and sticky with filaments, suggesting fungal infections. It can also be seen at the beginning of colds, bronchitis and pneumonia. Yellow sputum can be seen in Pseudomonas aeruginosa infections, but also in purulent infections such as Staphylococcus aureus. Further tests are needed to confirm the bacteria of the infection. Different periods of the same disease: for example, in the early stage of pneumonia infection, the patient mainly coughs up yellow pus sputum, with the treatment, the color of the patient’s sputum changes from yellow pus sputum to white sputum, suggesting that the patient’s condition has improved. However, the color of sputum can not diagnose the disease, nor can it reflect the fundamental changes of the disease, if the cough and sputum have not improved or even aggravated, it is recommended to go to the hospital in a timely manner, to clarify the cause of the disease, and standardize the treatment under the guidance of the doctor.