New drugs and new discoveries--such as those concerning the use of individual genetic profiles to help customize dosages--have refined drug treatment. Drug companies' marketing efforts as well as patients' views and wishes influence physicians in their choice of treatment. Drug-drug interactions continue to be a common cause of admissions to hospitals. Instantaneous access to a patient's complete drug list and to reliable medical information in a computer-based drug-prescribing system will help ensure patient safety. It will also contribute to evidence-based choice of pharmacological principle, drug, method of administration and dosage and to better agreement between patient and doctor.