The yellow color attached to the nasal septum in the morning is considered to be caused by dry rhinitis, sinusitis or rupture of sinus mucus cysts. 1. Rhinitis: rhinitis secondary bacterial infection, the nasal mucosa is covered with yellow mucopurulent secretions, so you can see the phenomenon of sleeping in the morning with a layer of yellow nasal septum. 2. Sinusitis: patients due to nasal foreign body, trauma, bacterial infection or turbinate hypertrophy caused by poor sinus drainage, further leading to the emergence of inflammation in the sinus cavity. Patients may have pus, headache, nasal congestion, olfactory impairment and other manifestations, in which the pus is mostly yellow or yellow-green. 3. Sinus mucus cyst rupture: Sinus mucous membrane gland tube blockage, inflammation or perverse reaction and lead to capillary plasma retention in the submucous membrane, gradually expand, and eventually form a cyst. When the cyst is small, there may be no obvious symptoms, but when the cyst is enlarged and ruptured, a yellow liquid crust comes out from the affected side of the nasal cavity. If the phenomenon of yellow color attached to the nasal septum persists in the morning, it is recommended to consult a doctor for a clear diagnosis and follow the doctor’s instructions to standardize the treatment.