In recent years there has been a change in asthma pharmacotherapy, with considerably greater emphasis placed on the use of preventive therapy (inhaled corticosteroids and sodium cromoglycate) and less reliance on bronchodilator therapy. This study examined Tasmanian prescribing trends to determine whether the recommended changes in the treatment of asthma had transpired into practice and to compare the State prescribing trends with national Australian data. Computerized dispensing records, consisting of summarized monthly lists of all drugs dispensed, from almost one-third of all the community pharmacies within the State were retrospectively collected at intervals of 6 months between 1991 and 1994. Anti-asthma drugs were grouped into beta-agonists, inhaled corticosteroids, theophylline, ipratropium bromide and sodium cromoglycate, and quantities were converted to defined daily doses (DDDs)/1000 population/day, by extrapolation to the entire Tasmanian population. The Tasmanian data were compared with estimated national dispensing data for anti-asthma drugs provided by the Drug Utilization Subcommittee of the Pharmaceutical Benefits Advisory Committee. Tasmanian prescribing was generally similar to the national data, with large rises in the prescribing of inhaled corticosteroids (61% increase), ipratropium bromide (138% increase) and sodium cromoglycate (52% increase), and a decline in theophylline usage (43% decrease) over the period of the study. The prescribing of beta-agonists remained fairly stable over the period of the study, while there was a marked decrease in the ratio of dispensed DDDs of beta-agonists: inhaled corticosteroids (from 2.9 to 1.7). The overall usage of anti-asthma medication in Tasmania was found to be significantly higher than the national data for 1991 and 1992, with an April 1994 level of 74.7 DDDs/1000 population/day (an increase of 6% from April 1991). Tasmanian and national prescribing of anti-asthma drugs appears to have changed in line with current management guidelines, with greater emphasis on the use of inhaled corticosteroids. More attention could also be given to the prescribing of anti-allergy preventive drugs.