No side effects. Normal saline or normal seawater are not drugs. 0.9%NaCl solution is similar to the osmotic pressure of blood in human body, just like we usually hang a bottle of normal saline for infusion, and there is no burden to clean it. The nose is the filter of the human body, and it is the only organ that is not closed. Every day, 10000 kinds of bacteria enter. Therefore, long-term nasal washing is helpful to the health of nasal cavity and reduce the occurrence of diseases.

Nose washing with salt water must be carried out in two steps. Wash the nasal vestibule alone first, and then wash the deep nasal cavity. You can't rinse directly from one nostril to another nostril or directly to the depths of the nasal cavity, which will flush the dirty things in the vestibule directly to the depths of the nasal cavity. The deep structure of the nasal cavity is very complicated, and it is easy to accumulate dirty things (which is also the reason why some people can't blow out their noses). You will rush in the dirty things blocked from the outside. Therefore, we should also pay attention to this point when choosing the tools for washing nose with salt water.