According to major asthma management guidelines, long-acting beta2-agonists (LABAs) should be used only when asthma remains symptomatic in patients already receiving regular inhaled corticosteroids (ICSs). A large Cochrane systematic review provides evidence that LABAs are safe and beneficial in control of asthma; sub-group analyses indicating that this is true when ICSs are used and in their absence. Two other Cochrane systematic reviews have found that LABAs are more effective than regular short-acting beta2-agonists, and are as effective as theophylline with fewer side-effects. These reviews support guidelines in the use of LABA as additional therapy when asthma is inadequately controlled by ICS at moderate dose. However, guidelines may be too conservative, and more studies in stable mild asthma comparing their use and safety with placebo and ICS are required.