Although 6 functions of the nose such as smelling, respiration, climatization, cleaning and defending the respiratory tract from particles, speech production, facial expression and beauty are defined, the most important among these is the respiratory function. The main task of nasal breathing is to moisten, warm and purify about 12000 liters of air per day, and to prepare it in the most appropriate way for the lungs. Nasal breathing is also very important for lung and heart health. Nasal breathing is important for smelling. Therefore, olfaction is also adversely affected in people with nasal congestion. In addition, persistent mouth breathing due to nasal congestion may cause various symptoms by disrupting the physiology of the mouth and throat. There are various physiological conditions, mucosal, structural, congenital and tumoral diseases that cause nasal breathing. In this article, the importance of nasal breathing is emphasized, various diseases that cause nasal obstruction and their solutions are mentioned.