Between one third and half of all consultations result in a prescription, and general practitioners are responsible for more than 80 per cent of the use of reimbursed prescription drugs in Denmark. Good prescribing habits imply the use of a limited number of drugs of which the doctor has a good knowledge. The risk of inappropriate prescribing is higher among doctors who prescribe many different drugs. The prescribing habits of the individual physician are quite stable, and changes usually occur slowly and as a result of various influences, including scientific papers, specialist recommendations, meetings, colleagues, patients, and drug companies. Previous development initiatives were often based on the assumption that suboptimal prescribing practice was due to lack of knowledge. It was, thus, expected that easily understandable information alone could improve the prescribing in general practice. However, continuous medical education based on didactic methods such as lectures and clinical guidelines have proved ineffective. Quality development should include thorough problem identification and analysis, elucidation of barriers towards change, and a combination of several targeted interventions. The implementation of changes should be seen as a complex, slowly progressing process in which continuous evaluation should be carried out with a view to adjusting the interventions.