Following the pharmacovigilance crises of 2004 involving the use of Vioxx and antidepressants in minors, medicine regulators turned to big data, also called real-world evidence, to support their efforts to establish the safety of treatment protocols. In many areas of drug development, big data can clearly play a part; but to date, it has not helped resolve safety issues. Developments in artificial intelligence may help clarify the respective roles of big data and clinical expertise in pharmacovigilance in surprising ways.