There are three main reasons for having a runny nose: First, it may be related to the working environment of the patients, such as workers in construction sites or workers in cement factories, who are often exposed to dust and powder, which are especially likely to stimulate the congestion and inflammation of the mucous membrane of the nasal cavity of the patients, so the noses of the patients are often runny. Secondly, the main consideration is upper respiratory tract infection, after the upper respiratory tract infection, the patient’s nose will often have runny nose, sometimes yellow-purulent color, often accompanied by bacterial infection. Third, the main consideration is that the patient has rhinitis, especially allergic rhinitis patients may often run clear water-like nasal discharge, like a stream of water, accompanied by nasal congestion, itchy nose and continuous sneezing in severe cases. So no matter which of the above causes triggers the runny nose, it must be actively dealt with.