There are mainly the following clinical conditions, each of which has a different treatment plan. The first is rhinitis, sinusitis, due to the swelling of nasal mucosa, nasal secretions blockage, resulting in the air can not reach the smell area, thus patients appear to smell things can not smell, for this case generally carry out active drug treatment rhinitis, sinusitis, patients nasal ventilation improved, the general sense of smell will be significantly restored. The second condition is that the patient’s nasal cavity or olfactory fissure has grown something, such as nasal polyps or olfactory neuroblastoma. In this case, the air cannot enter and reach the olfactory area, resulting in poor or lost sense of smell. In the third case, there are patients with viral infections that invade the olfactory nerve, resulting in degeneration and necrosis of the olfactory nerve, so in this case, it is difficult to recover from the smell.