Current concerns over the safety of medicines once they have been marketed mean that pharmacoepidemiology is of increasing importance. There are three main areas in which further research is needed. 1 To improve the methods used to make causal inference of effects of medicines and to raise the quality of the reporting and critical appraisal tools, so that the strengths and weaknesses of the new methods can be judged. 2 To apply the methods in areas where randomized trials cannot easily be done, such as in pregnancy. 3 To use electronic health records as fully as possible, using linkage between different databases, ensuring the data are of as high quality as possible. Public health and public perceptions mean that much of pharmacoepidemiology must be done using non-industry funding sources.