This study compared, for the first time in the United Kingdom, the efficacy and safety of oral 100 mg and subcutaneous 6 mg sumatriptan within a patient for the acute treatment of migraine. The patient's preference for the two formulations of sumatriptan were also recorded. The study was a multicentre, randomized, open, crossover design with an optional open parallel group extension. Individual attacks were treated with one formulation only. Over 70% of patients who treated attack 1 in both treatment periods of the crossover phase reported headache relief with each formulation at 4 h. Only 3% of patients failed to respond to at least one of the formulations at this time point. At the end of the crossover phase patient preference for the injection more than doubled from the pretreatment level in those patients who were previously naive to sumatriptan. During the optional phase of the study, 38% of patients chose to treat some attacks with oral and some with subcutaneous sumatriptan. The main reason for choosing injection was speed of relief, whilst convenience was the major reason for the use of the tablet.