The causes of coughing up small yellow particles that smell bad include food debris, tonsil stones, tonsil crypt infections, and so on. Commonly used treatment methods include daily life management, medication, surgical treatment and so on. 1. Food debris: Since food debris is easy to stay in the crypt, it will be corrupted for a long time and produce a foul odor. When coughing violently, small yellow smelly particles will be coughed up. Patients can keep their mouths clean and hygienic by rinsing and brushing their teeth regularly to avoid the retention of food residues. 2. Tonsil stones: due to the recurrence of tonsil inflammation, easy to form stones. Due to the long time adherence to the tonsils, they appear as yellow particles, accompanied by a foul odor. Tonsil stones can be cleaned out by laser treatment or rinsing, and tonsillectomy can be performed if necessary. 3. Tonsil crypt infection: due to the poor circulation of the tonsil crypt, caused by the shedding of mucosal epithelium, bacteria and other deposits in the tonsil crypt, the formation of foul-smelling yellowish-white secretion. This may be manifested by coughing up foul-smelling granular secretions. Medications such as penicillin and levofloxacin can be used to control the inflammation and infection, and tonsillectomy can be performed if necessary. In addition, there may be other reasons for coughing up small yellow particles of very smelly cough, such as symptoms do not improve or aggravate, it is recommended that patients go to the hospital in a timely manner, improve the examination, follow the doctor’s instructions, so as not to delay the condition.