The reason for putting the two medicines together in one single inhaler is that they work on different aspects of asthma. Used together, budesonide and formoterol provide better control of asthma than a single treatment, decreasing the number of asthma attacks. Symbicort provides both medications in the same single inhaler, so that treatment is more convenient for the patient:  

• Budesonide (see Pulmicort) is a type of medicine called a steroid (of the glucocorticosteroid type), which treats the long-lasting (chronic), underlying part of asthma.
  
  
  • This is the inflammation - the "quiet part" of asthma that you cannot hear, see, or feel.
    
    
  • When it is left untreated, inflammation can worsen. The lungs can become more inflamed and asthma symptoms and attacks can increase.
    
    
• Formoterol (see Oxis) is a fast and long-acting bronchodilator. Bronchodilators are medicines that open up the air passages (bronchial tubes) of the lungs.
  
  
  
  • It is used to treat the symptoms of bronchial asthma, chronic bronchitis, emphysema, and other lung diseases.
    
    
  • It relieves cough, wheezing, shortness of breath, and troubled breathing by allowing an increased flow of air through the bronchial tubes.