Nasal congestion, yellow and thick nasal mucus, the possible causes are colds, sinusitis, chronic rhinitis and so on. 1. Cold: this is the most common clinical acute infectious diseases of upper respiratory, mostly viral infections secondary to bacterial infections, and its typical symptoms are nasal congestion, yellowish pus nasal discharge, cough, sore throat and so on. 2. Sinusitis: often caused by viral, bacterial or fungal sinus infection, its main clinical manifestations are nasal congestion, runny nose, headache, loss of smell or loss of sense of smell. 3. Nasal foreign body: Nasal foreign body, stimulate the nasal mucosa, easy to secondary bacterial infection, increased secretion, yellow sticky nasal mucus and nasal congestion. It is recommended that people with related symptoms should actively consult a doctor for a systematic examination and standardized treatment after a clear diagnosis.