Nasal inhalation is the process of breathing in air or substances through the nose. This method allows for the direct delivery of medications, such as nasal sprays or inhalers, to the respiratory system. It is often used for treating conditions like allergies, sinusitis, and asthma, as it can provide quick relief. The nasal passages are lined with mucous membranes that help filter and humidify the air. When substances are inhaled through the nose, they can be absorbed more rapidly into the bloodstream compared to other methods, making nasal inhalation an effective route for certain therapies and medications.