Root canals do not usually cause patients to develop nasal disorders. Yellow water from the nose may be caused by sinus mucous membrane cysts, rhinitis, sinusitis and other reasons. 1. Sinus mucous membrane cysts: long-term inflammation and thickening of the mucous membrane of the sinuses, which in turn leads to the accumulation of fluid under the mucous membrane and the formation of cysts. After the formation of cysts, the larger the cysts, the stronger the pressure, after the rupture of the nose will appear yellow water. 2. Rhinitis: Rhinitis is usually caused by bacterial infection, bacterial infection will cause purulent inflammatory infection of the mucous membrane of the nasal cavity and sinuses, with yellow nasal discharge as the main cause. 3. Sinusitis: If the sinus mucosa has a chronic inflammatory reaction, the color of the nasal mucus will become yellow, mostly related to Staphylococcus aureus infection. At the same time, the sinus cavity of the sinus is relatively large, but the sinus opening is relatively small, so the nasal mucus in the sinus cavity stays longer, will also flow yellow nasal mucus. If the symptoms of yellow water coming out of the nose from root canal treatment persist without relief, you need to seek medical treatment in time.