Inhaled corticosteroids reduce airway inflammation and bronchial hyper-responsiveness in asthma. Their regular use is associated with a reduction in morbidity and mortality from asthma. International guidelines recommend their use as first-line treatment in asthma and the dose should be increased stepwise in accordance with asthma severity. Short-acting beta2-agonists are recommended for use as reliever medication for the acute relief of symptoms. Long-acting beta2-agonists have a sustained bronchodilator action but are not recommended for use as monotherapy in asthma, particularly because they lack clinically relevant anti-inflammatory action. The seminal observation in a controlled trial that the addition of salmeterol to low-dose inhaled beclomethasone dipropionate was superior to doubling the dose ofthe beclomethasone dipropionate was followed by several well-controlled studies that confirmed this observation. These included multinational and multicentre trials in large numbers of patients and the use of different inhaled corticosteroids and the two long-acting beta2-agonists, formoterol and salmeterol. Therefore level A evidence (randomized controlled trials with a rich body of evidence) is available for this recommendation. Based on this, updated asthma guidelines recommend the addition of long-acting beta2-agonists for chronic asthma that is at least moderately severe or mild asthmathat is not well controlled with low-dose inhaled corticosteroids. Attention was therefore focused on developing combination inhalers that included inhaled corticosteroids and long-acting beta2-agonists in order to simplify asthma treatment and improve adherence to prescribed medication. Symbicort Turbuhaler (budesonide/formoterol in a single inhaler) is one such development. Studies to date in over 800 adult patients have confirmed that budesonide/formoterol is superior to double the dose of budesonide monotherapy and at least as effective and safe as budesonide and formoterol in separate inhalers, These studies also demonstrate that there are no physico-chemical interactions when the two medications are combined in a single inhaler. Symbicort in its easy to use formulation and inhaler device represents a valuable addition to the pharmacological management of asthma.