Coughing up small yellow particles may be the product of the solidification of physiological thick phlegm fluid, or tonsil stones or dental calculus. 1. Physiological thick phlegm: If you do not pay attention to oral hygiene for a long time, lack of moisture, phlegm in the throat storage for too long, will lead to phlegm more and more thick, and ultimately solidified particles will be formed with the cough out of the body. This is a normal phenomenon, can be relieved by adding more water. 2. Pathological causes (1) Tonsil stones: Tonsil stones can be caused by tonsillitis, or formed by food debris, bacteria and mucus aggregation. If it is caused by inflammation of the tonsils. If it is caused by food debris and bacteria gathering due to long-term lack of attention to oral hygiene, it can be cleaned regularly with oral cleaning agents. (2) dental calculus: if you often do not brush your teeth or brushing habits are not good, long-term accumulation of oral cavity will appear dental calculus, calculus off will also appear yellow particles. Need to develop good brushing habits, inhibit the continued formation of dental calculus. If the calculus is more serious can go to the regular hospital stomatology consultation, through the cleaning cleaning. If the occasional cough yellow particles, pay attention to changing lifestyle habits, drink more water, if the regular cough yellow particles, should go to the regular hospital specialists.