Intravenous aminophylline is effective in children with acute asthma and was the bronchodilator of choice for many years. However, with the advent of inhaled b agonists and anticholinergic agents an alternative, less invasive, therapeutic strategy is currently available. If children with acute asthma fail to respond to inhaled therapy clinicians may consider aminophylline a controversial treatment. The published evidence on whether aminophylline produces further beneficial effect in children already receiving inhaled therapy for acute asthma is reviewed in this paper. The published randomised controlled trials comparing aminophylline with placebo are of good methodological quality, although the numbers of children in many of the studies are small. Trial outcomes included lung function (FEV1 and PEF) and clinical scoring of asthma severity. Aminophylline improved percentage predicted FEV1 by 6 hours, and this effect was maintained for 24 hours. Improvements were also seen in clinical asthma severity scores at 6 hours. Despite improvements in lung function and asthma severity, there was no reduction in hospital stay or the number of nebulisers required. The main side effect of aminophylline therapy was an increased incidence of vomiting. In conclusion, the addition of intravenous aminophylline should be considered early in the treatment of children hospitalised with acute severe asthma with suboptimal response to the initial inhaled bronchodilator therapy. Further research should be carried out to examine whether intravenous aminophylline may have a beneficial effect in other settings such as intensive care to determine if it may reduce intubation and ventilation rates.