When the baby has a runny nose, it may lead to breathing difficulties. To deal with the symptoms of runny nose properly, mothers should first understand the causes of runny nose in babies. Firstly, runny nose caused by cold, rhinitis caused by cold is called acute rhinitis, at this time the mucous membrane of nasal cavity is congested and swollen, and the secretion of glands increases, that is to say, nasal mucus is formed, which is clear water-like at the beginning, and gradually becomes pus after 3-5 days, and then gradually heals. Secondly, allergic rhinitis, often with clear runny nose and accompanied by nasal congestion, nasal itching, sneezing and other symptoms, especially in the early morning after waking up. Thirdly, there is a foreign body in the total cavity, if the baby’s side of the nasal cavity has a foul smell, runny snot, sometimes with blood in the snot, you need to consider whether there is a foreign body in the nasal cavity. Fourthly, acute and chronic rhinitis, when the baby has sinusitis secondary to acute and chronic rhinitis, there will often be a lot of nasal mucus, which seems to flow incessantly, and sometimes accompanied by headache. Fifth, nasal polyps, individual babies only unilateral nasal discharge, but blowing can not blow out, nostrils are not ventilated, sleep snoring, be alert to the presence of nasal polyps.