What is Symbicort? Symbicort contains a combination of budesonide and formoterol. Budesonide is a steroid that reduces inflammation in the body. Formoterol is a bronchodilator that relaxes muscles in the airways to improve breathing. Symbicort is used to prevent bronchospasm in people with asthma or chronic obstructive pulmonary disease (COPD). This medicine is for use by adults and children who are at least 6 years old.