There are a variety of causes for a buildup of phlegm in the throat, one of which involves problems with the tonsils, the areas of lymphoid tissue on either side of the back of the throat. The tonsils act as part of the body’s immune system and their job is to help prevent infection, particularly upper respiratory tract infections.

Occasionally, the tonsils themselves can become infected and develop tonsillitis. This may be the result of a virus or bacteria in the throat. Sometimes people develop tonsil stones on the back of their tongue or throat. These are small whitish bumps that can be popped and are caused by bacteria collecting in the pockets of the tonsils, often leading to a sore throat, phlegm in the throat, earaches, bad breath, and coughing.

Many times, tonsil stones can be treated by removing them with a Q-tip or using pulsating water jets to remove them. In more severe cases, the tonsils themselves can be surgically removed in a relatively routine procedure.

Throat phlegm, or mucus, is produced by cells lining the nasal passage, and its purpose is to trap tiny particles, such as dust, and prevent them from entering a person’s respiratory system. Normal phlegm is clear and thin, while green, yellow, or grayish mucus can indicate an infection resulting from bacteria that have become trapped in the throat. Excessive amounts of phlegm in the throat can lead to difficulty breathing or swallowing, coughing, and sore throat, and a general physical examination is recommended.