Two different patient education programmes for asthma in general practice were evaluated in a controlled trial. Knowledge, self management, and morbidity due to asthma were assessed in 339 patients by means of a questionnaire. One group then received a maximum education programme, a second group received a limited education programme, and a third acted as a control group. 274 patients were reassessed after one 1 year. In both the intervention groups, understanding of asthma was greater after the trial. Only in the maximum intervention group was a significant improvement in knowledge of asthma shown. Neither group showed any change in self-management ability or asthma morbidity that differed significantly from changes in the control group. These simple informational education programmes were ineffective when applied to a general practice population. Further studies of factors affecting attitudes, beliefs, and actions are needed to improve the advice and support given to asthma patients.