There is no fastest solution to cough with phlegm in children, it may be due to upper respiratory tract infections, pediatric bronchitis, tuberculosis and other diseases, which need to be treated symptomatically and causally. 1. Symptomatic treatment: coughing up phlegm is the body’s normal way of expelling germs, you can drink more water, keep the respiratory tract moist, take honey and so on to relieve throat discomfort. If coughing up phlegm is serious, you can use phlegm remedies such as Ambroxol and Acetylcysteine under the guidance of your doctor. 2. Treatment for the cause. (1) For upper respiratory tract infection, if the child has no other symptoms, no further special treatment is needed, and the disease is mainly treated symptomatically. (2) for pediatric bronchitis, if the influenza virus is caused, the child needs to follow the doctor’s instructions to apply neuraminidase inhibitors, such as oseltamivir phosphate, etc.; if it is caused by bacterial infections, it is necessary to follow the doctor’s instructions to apply amoxicillin, ceftriaxone and other antibiotics. (3) For tuberculosis, the child may need to cooperate with the doctor to apply chemotherapeutic drugs, such as isoniazid, rifampicin and ethambutol. There are many reasons for children to cough up phlegm, they should go to the hospital, do the relevant examination, clarify the cause of the disease and then carry out standardized treatment. All of the above medications should be used under the guidance of a doctor, avoid self-medication.