Children’s throat inside the old spit may be sinusitis, laryngitis, bronchitis and other diseases. 1. Sinusitis: Sinusitis may be caused by upper respiratory tract infection, rhinitis, deviated nasal septum and other factors. The child may have cough and pus, when the pus flows to the pharynx and larynx, it can irritate the mucous membrane of nasopharynx or pharynx, causing cough and phlegm symptoms. 2. Laryngitis: Laryngitis may be caused by pathogen infection, inhalation of harmful gases and dust, and lower respiratory tract infection. Children may have symptoms such as increased secretion, laryngeal discomfort and coughing up phlegm. 3. Bronchitis: The causes of bronchitis include low immunity, dry climate, microbial infections and seasonal changes. Affected children may have symptoms such as coughing, coughing up phlegm, wheezing and shortness of breath. There are many reasons why children spit up all the time. Parents are advised to bring their children to regular hospitals for relevant examinations so as to find out the cause of the disease. Once the diagnosis is confirmed, it is necessary to actively cooperate with the doctor to take relevant treatment measures.