The cause of a toddler’s runny nose may be a common cold or allergic rhinitis. The causes are treated differently and should be seen promptly. Common treatments include general treatment and medication. 1. The runny nose caused by common cold is accompanied by fever, fatigue, sore throat and other symptoms, and the nasal mucus will change from the original clear nasal mucus to white or yellow pus mucus. Usually the duration of common cold is 7~10 days, and some babies can be relieved by themselves. 2. Runny nose caused by allergic rhinitis, mainly manifested as nasal congestion, open-mouth breathing, snoring, wheezing, feeding difficulties, rubbing the eyes, rubbing the nose, etc. Usually, the symptoms of allergic rhinitis will last for 2 weeks, and may be accompanied by allergic dermatitis, allergic cough, and need to follow the doctor’s instructions to use antiallergic drugs, such as antihistamine (loratadine syrup), and so on. If your baby has other complications due to runny nose, such as high fever, vomiting, etc., you need to consult a doctor to clarify the cause of the disease and then treat the cause under the guidance of the doctor.