<i>Background:</i> Drugs may be prescribed in combinations causing drug-drug interactions (DDI) and adverse drug reactions (ADR), resulting in hospital care. <i>Methods:</i> To provide prescribers of drug therapy with a better knowledge of individuals’ current drug therapy, governments have started to collect prescribing data. <i>Results:</i> The data on individuals’ dispensed drugs is available for prescribers, pharmacists, and the registered individuals in Sweden and Denmark. The information has not yet come to an extensive use in healthcare. Pilot projects have been reported positively, but accessibility has to be improved. <i>Conclusions:</i> To avoid DDIs, reliable information on all drugs used by each single individual needs to be available at the point of care. Knowledge databases about clinically relevant DDIs must be updated and accurate. To tailor the magic bullet for the individual, new genomic- and proteomic-based knowledge about the individual has to be considered in the future.