Pharmacovigilance involves the assessment of risks and benefits of medicines. There are legal and regulatory aspects of this process, and the licensing of a new medicine is always provisional. The systems, in the past, have had limited statistical involvement, either in terms of personnel who are statistically trained, or in terms of statistical methods. This is changing. The high profile activities of pharmacovigilance have often been emergencies, though most is routine activity. Application of statistical thinking and of techniques is being done to help detect adverse effects of medicines rather earlier so that some emergencies may be avoided.