Runny nose refers to the mucus or plasma secretions in the nasal cavity through the nasal cavity, the baby’s breathing is not smooth, there will be nasal congestion, causing the baby’s runny nose for many reasons, the most common is the child’s cold, in the early stage of the cold nasal mucus is watery, thin secretions, transparent like clear water, for vascular exudate and mucus mixture, containing shed epithelial cells, white blood cells, a small amount of red blood cells and mucin, while in the late stage of the cold can appear It can also be accompanied by fever, generalized aches and pains, malaise and other symptoms. Inflammation in the nasal and pharyngeal cavities during a cold stimulates the nasal cavity to secrete mucus, or what we call nasal discharge, which then drains away these pathogenic bacteria by flowing out. Allergic rhinitis can also be caused by a runny nose. If your baby has a stuffy nose and a runny nose especially in the morning or before going to bed at night, sneezing also increases, and the runny nose is mostly white and clear with a high volume, you need to consider allergic rhinitis. Some babies are naughty and will stuff some small things into their nostrils, these foreign objects will cause unilateral nasal discharge or with blood, then you need to take out the foreign objects in time to avoid blocking the nostrils. The above are the common causes of nasal congestion and runny nose in babies, if the runny nose persists on time, parents need to take their babies to the hospital in time for early treatment so as not to delay the condition.