Data on health outcomes resulting from the use of medicines provide important evidence of cost-effectiveness. Currently, clinical information on individual patients, collected by Medicare Australia to assess eligibility for subsidised treatment with high-cost medicines, is inaccessible for research. Comprehensive data on drug use and health outcomes should be made accessible, with appropriate regulation, so that the effectiveness, utility and appropriateness of our systems of access to medicines can be independently analysed. In the interests of continuous improvement in medical care and optimal use of limited resources, we strongly advocate the enhancement of Medicare Australia databases and liberalisation of arrangements for access to administrative and clinical data.