Aim: To evaluate the efficacy and tolerability of formoterol delivered by Aerolizer in the emergency department. Methods: A single-centre, double-blind, randomised, placebo-controlled, parallel group study was conducted in patients seeking emergent care for an acute exacerbation of asthma. Patients were randomly assigned to one of two groups: group 1 (salbutamol), receiving a total dose of 600 mg salbutamol (200+200+200) delivered by a meter-dose inhaler into a spacer device as two puffs at 20 min intervals; and group 2 (formoterol), receiving formoterol 24 mg (12+12) as two dry powder capsules each containing 12 mg of formoterol via Aerolizer at 20 min intervals. The peak expiratory flow rate (PEFR) was measured at baseline and 5 min after the second and third doses. Results: 60 subjects receiving salbutamol (n = 28) or formoterol (n = 32) completed the study. Age, gender, baseline PEFR, duration of asthma and previous medication were balanced between the two groups. Mean PEFR increased significantly over baseline values in both the salbutamol and formoterol groups (63% in the salbutamol group, p = 0.001, and 55% in the formoterol group, p = 0.001). No significant difference was observed in the increase in PEFR between the groups (p = 0.99, 95% CI 229.62 to 29.59). The proportion of patients reporting adverse events was similar in the two groups. Conclusion: Formoterol was found to be well tolerated and as effective as salbutamol in the management of acute asthma. Further studies are needed to follow the patients after discharge from the emergency room to compare the long-term effect of formoterol on patients' stability.