Budesonide powder inhalation is a specific type of glucocorticoid used primarily for the control of bronchial asthma and chronic obstructive pulmonary disease. It is a glucocorticoid with potent local anti-inflammatory effects that enhances the stability of endothelial cells, smooth muscle cells and lysosomal membranes, thereby inhibiting the immune response and reducing antibody synthesis. It can reduce the release of allergy-active mediators such as histamine and its activity will be reduced, and it can reduce the enzymatic process stimulated by antigen and antibody binding, inhibit the synthesis and release of bronchoconstrictor substances, and thus can reduce the contractile response of bronchial smooth muscle. However, it has certain side effects if used in large amounts, such as weight loss, atrophy of lymphoid tissue and adrenal cortex, but the side effects are much weaker than other systemic hormones.