Yellow water flowing from the nose may be caused by malignant tumors of the nasal sinuses, acute and chronic sinusitis, nasal mucous membrane cysts or nasal vestibulitis. You can’t judge whether it’s a precursor of a serious illness by this symptom, and you need further examination to make a clear diagnosis. 1. Nasal sinus malignant tumor: when there is a malignant tumor in the nasal sinus, combined with bacterial infection and necrosis, it will lead to yellow water flowing from the nose, which may be accompanied by nasal congestion, nosebleed and other abnormal manifestations. 2. Acute and chronic sinusitis: usually associated with infectious factors, when the infection is aggravated, it may form purulent nasal mucus, yellow pus nasal mucus, which will lead to yellow water flowing from the inside of the nose, and may be accompanied by dizziness, headache and other symptoms. 3. Nasal mucous membrane cyst: it may be related to the blockage of mucous gland ducts, chronic infection and other factors, when there is a rupture of the cyst, yellow fluid may appear inside the cyst, and there will be yellow water flowing out. 4. Nasal vestibulitis: it may be caused by local skin damage and environmental factors, which may lead to local skin erosion, and it will make the local oozing of yellowish liquid, but the amount of liquid is small. Nose yellow water, and there are other abnormal performance, it is recommended to seek medical treatment as soon as possible, systematic examination, clear diagnosis, to avoid delaying the condition.