Budesonide (Budecort) is a corticosteroid medication used for long-term management of conditions such as asthma, COPD, allergic rhinitis, and inflammatory bowel diseases. It acts by binding to glucocorticosteroid receptors to reduce inflammation and hyper-reactivity in airways, with administration forms including inhalers, nasal sprays, and oral capsules. Potential side effects include headaches, gastrointestinal disturbances, and local nasal irritation, and it is contraindicated for acute asthma episodes and specific patient hypersensitivities.