Sneezing with a rotten fishy odor may be due to sinusitis, nasal foreign body, atrophic rhinitis and other causes. 1. Sinusitis: when there is inflammatory disease in the sinuses, there may be more thick secretions accumulated in the nasal cavity, and these secretions cannot be discharged after long-term accumulation, so there may be a rotten fishy odor when sneezing. 2. Nasal foreign body: If the patient has a foreign body in the nasal cavity for a long time, leading to infection in the nasal cavity, there may be a rotten fishy odor when sneezing. 3. Atrophic rhinitis: due to infection in the nasal cavity and microbial reproduction and thus cause nasal mucosa atrophy, if the symptoms are more serious, there are a large number of dry nasal crusts in the nasal cavity, resulting in sneezing with a rotten fishy odor. When patients sneeze with a rotten fishy smell may also be other diseases, it is recommended that patients go to the hospital for examination, and under the guidance of the doctor for targeted treatment.