The main causes of runny nose in children include the following: first, the symptoms caused by sinusitis in children. Children with sinusitis will have nasal congestion, yellow pus nasal discharge, accompanied by dizziness, headache and lack of mental clarity. Children with sinusitis can be diagnosed with sinus CT in time, and after the diagnosis of sinusitis, children can be treated with rinsing under the nasal endoscope. Secondly, children with wind-heat colds may suffer from symptoms. If a child has internal heat and feels the evil of wind-heat, the evil of wind-heat will attack the lungs and nasal orifices, resulting in cough, nasal congestion, yellow pus nasal discharge, etc. Children can be given timely treatment to clear the wind-heat, such as the application of mulberry chrysanthemum drink.