Three months baby runny nose cough can be seen in acute upper respiratory tract infection, acute bronchitis, etc., can use saline nasal spray, oral cough expectorant drugs symptomatic treatment, if necessary, anti-infection. 1. Acute upper respiratory tract infection: often caused by viral infections, nasal congestion, runny nose and other local symptoms, mostly self-limiting, can be relieved within a few days, runny nose can be used to spray saline nasal congestion, swabs carefully clean up nasal secretions. Cough is usually mild, and in severe cases, oral cough suppressant can be taken. 2. Acute bronchitis, bronchopneumonia: In the early stages of the disease, there are symptoms of upper respiratory tract infections, followed by coughing, and progressive aggravation, may be accompanied by fever or wheezing. For treatment, saline nasal spray can be used to alleviate the symptoms of runny nose, and oral amiloride oral solution can be taken to relieve cough and expectorant symptoms. For severe cough, glucocorticosteroids (e.g. budesonide) should be used to carry out nebulization treatment, and if bacterial (or Mycoplasma pneumoniae) infection is considered, cefaclor (or azithromycin) should be used to treat the infection, and if the condition is severe, intravenous fluids should be given to treat the disease. All of the above medications should be used under the supervision of a physician, and it is recommended to actively seek medical attention and evaluation of treatment by a specialist.