The treatment of asthma in children should not be fixed but rather must be regularly adapted to keep the condition under control defined according to clinical and functional criteria. In a child whose asthma is controlled, a step down in therapy should be carried out every 3 to 6 months to achieve the minimal effective level of treatment. In a child whose asthma appears not to be controlled, it is necessary initially to evaluate compliance with therapy and to seek aggravating factors which may include allergic rhinitis, multiple sensitisation, tobacco exposure, psychological factors, obesity, gastro- oesophageal reflux and infection. Where control of asthma is poor the main therapeutic strategy rests on an increase in the dose of inhaled corticosteroid and on the addition of other anti-asthmatic treatments--inhaled long--acting beta 2 agonists and oral leukotriene antagonists.