Inhalation therapy is a common treatment for respiratory diseases, including aerosol inhalation, aerosol inhalation via aerosol cans, dry powder inhalation, and nebulized inhalation, with nebulized inhalation having the most definite efficacy and the broadest indications. However, information on the dosing regimens and drug combinations for nebulized inhalation therapy is very limited. Recently, the American Society of Health-System Pharmacists published a guideline for mixing and combining commonly used nebulized inhalation drugs [1], which provides various recommendations for the drugs available for nebulized inhalation and their combinations in a table format for clinicians to understand and grasp. Based on this guideline, the expert group on nebulized inhalation therapy for chronic airway diseases in adults formulated a consensus on nebulized inhalation drug therapy based on the current situation of nebulized inhalation therapy for respiratory diseases in China, and at the same time proposed recommended nebulized therapy protocols according to different diseases for clinicians’ reference. Inhalation therapy can be divided into wet chemotherapy and nebulization therapy: Wet chemotherapy is a device that evaporates water or solution into water vapor or aerosol consisting of 0.05-50 μg droplets to increase the humidity of the inhaled gas, moisten the airway mucosa, dilute the sputum, and maintain the effective contouring ability of mucus cilia movement. Nebulized therapy applies a specially designed aerosol generating device to form liquid droplets or solid particles of aerosol of water and drug solution, which are inhaled and deposited in the respiratory tract and alveolar target organs for the purpose of treating diseases and improving symptoms, while nebulized inhalation also has a certain effect of humidifying the airway [2]. When a physician decides to use nebulized inhalation therapy, he or she must also decide which inhalation device to use. The main nebulizer inhalation devices available today are small volume nebulizers (SVN), such as jet nebulizers, and ultrasonic nebulizers (USN), both of which have advantages and disadvantages. Jet nebulization is the most commonly used nebulization method, oxygen can be used as the jet nebulization gas source, but must pay attention to the pressure and flow rate used. Comparatively speaking, the pressure and flow rate of the gas source generated by compressed air pumps are more constant, and the homogeneity of the treatment effect is more comparable and more suitable for comparing clinical efficacy. Ultrasonic nebulization may be detrimental to some drugs such as protein or peptide-containing compounds due to the violent shock of ultrasound that warms the liquid in the nebulization vessel. Ultrasonic nebulization is also less effective than jet nebulization for suspensions (e.g., glucocorticoid solutions). In addition, in some patients prone to CO2 retention (e.g., COPD with respiratory failure), high-flow oxygen nebulization inhalation can exacerbate CO2 retention while rapidly increasing PaO2. On the other hand, nebulized inhalation of bronchodilators in patients with bronchial asthma can lead to a short-term decrease in arterial partial pressure of oxygen due to changes in the V/Q ratio, and pre-oxygenation or nebulized inhalation of oxygen may be beneficial in these patients [5]. For nebulized inhalation therapy, high volume USN is used if continuous application or wetting of the inhaled gas is required.