Phlegm is mucus that usually appears when you are coughing. If you notice, the color of phlegm is not always the same. Do not underestimate the change in color of phlegm, because the color of sputum can indicate certain diseases. Besides being clear, the color of phlegm can change to white, green, yellow, red, pink, and even black. Try to look at the color of phlegm that comes out when you cough. In addition to being a sign to estimate the underlying cause of complaints, sputum discoloration can also be an indicator of the degree of disease course. For clarity, consider the sputum color changes and possible causes below. Clear phlegm The phlegm produced by the body contains dissolved proteins, water, antibodies, and salts. This phlegm acts to moisturize the respiratory system in the body. Cough with clear phlegm is often caused by a viral infection, or an allergic reaction to the respiratory system. White phlegm White phlegm usually indicates several diseases such as: Viral b