A four-year-old baby who does not cough during the day and coughs hard at night may be caused by allergic cough, gastroesophageal reflux, sinusitis, etc. The condition can be improved by general treatment, medication and surgery. 1. Allergic cough: Generally, the symptoms can be improved after staying away from allergens. Severe allergies can be treated with glucocorticosteroids, such as budesonide suspension for inhalation, under the guidance of a doctor. 2. Gastroesophageal reflux: patients should pay attention to dietary adjustments, avoid eating chocolate, coffee, candy and other foods, and should not eat within 2 hours before bedtime. Acid-suppressing drugs, such as omeprazole, can be taken as prescribed by the doctor for treatment. For children with serious conditions, surgery should be considered. 3. Sinusitis: patients should drink more water, pay attention to rest, and avoid picking and digging their nostrils. Antibiotics, such as amoxicillin, can be taken under the guidance of the doctor. Conservative treatment is ineffective patients can be treated with nasal endoscopic surgery. It is recommended that patients strictly follow the doctor’s instructions to use medication, actively cooperate with the doctor’s treatment, pay attention to monitoring the condition in life, and promptly consult a doctor if there is any abnormality.