Inhaled beta 2-adrenergic agonists have been used in the treatment of asthma since the 1970's. They are extremely effective bronchodilators in all situations of bronchoconstriction, and are generally well tolerated by patients. The recent advent of long-acting beta 2-adrenergic agonists will extend the clinical applications of this group of drugs. On the other hand, doubts have recently emerged on the safety of inhaled beta 2-adrenergic agonists. Recent well controlled studies also examined the manners whereby inhaled beta 2-adrenergic agonists are used in asthmatics, and the long term effects on lung functions. Although at least two decades have passed since the introduction of inhaled beta 2-adrenergic agonists, strategies on their optimum use have only emerged from these recent findings. This review briefly discusses as the most important developments leading to the rationalisation of the way inhaled beta 2-adrenergic agonists should be used in clinical asthma.