Symbicort is a novel asthma product containing both budesonide and formoterol in a single inhaler, Turbuhaler. Budesonide is a corticosteroid that treats underlying airway inflammation in asthma; formoterol is a rapid- and long-acting beta2-agonist that prevents and reverses airway obstruction. Budesonide and formoterol therefore have complementary effects, treating two different components of asthma. Clinical studies have shown that Symbicort is more effective in the treatment of asthma than double-dose corticosteroid, and clinical experience to date indicates that Symbicort is at least as effective and well tolerated as budesonide and formoterol given in separate inhalers. Symbicort has a fast onset of effect, which may help patients feel more in control of their condition and improve adherence to their medication, and a long duration of effect that allows twice-daily or even once-daily dosing during periods of good control. More convenient treatment represents another important benefit for patients with asthma, as ease of use can also result in improved adherence, leading to better disease control.