Budecort (Budesonide) is used to help prevent the symptoms of asthma. When used regularly every day, inhaled budesonide decreases the number and severity of asthma attacks. However, it will not relieve an asthma attack that has already started. Budesonide is a corticosteroid or steroid (cortisone-like medicine). It works by preventing inflammation (swelling) in the lungs, which makes the asthma attack less severe.