The main reason for bad breath in rhinitis is the secretion of rhinitis-sinusitis and inflammation of the oropharynx. 1. Rhinitis secretion: rhinitis patients will seep out a lot of secretion due to itself, the secretion contains protein and other components are easy to rot in the nasal cavity, corruption decomposition, ammonia, etc. resulting in a foul odor, the nasal cavity and the oropharyngeal cavity are connected, so rhinitis patients will have bad breath. 2. Oropharyngeal inflammation: rhinitis patients often due to the nasal cavity, the oropharyngeal cavity connected to the backflow of nasal mucus into the oropharynx, backflow of nasal mucus can cause the oropharynx inflammatory reaction such as laryngitis, so patients with rhinitis will have bad breath. Rhinitis patients have bad breath, it is recommended that patients under the guidance of a professional doctor for active treatment.