A large or small nostril is often caused by congenital cleft lip and palate or nasopalatine cleft, resulting in different nostril sizes, which accounts for a large proportion in clinical practice. If we exclude the congenital diseases, if there is a deviation of the nasal septum in the process of growth and development, or if the nasal deformity heals due to trauma, it will also lead to a large and small nostril. Of course, if you look carefully at everyone’s nostrils, they are not completely symmetrical and the same size, but not very obvious. If they are more concerned about the different sizes of nostrils, they can consider cosmetic surgery to correct the deformity after the age of 18 years.