The restricted application of clinical trials has trig- gered the adoption of pharmacoepidemiology studies and pointed out the potential contribution of this disci- pline. Firstly, pharmacoepidemiology studies could supplement the information available from premarketing studies, such as in patients not studied prior to market- ing or in patients with concomitant diseases and medica- tions. Secondly, pharmacoepidemiology studies provide new discoveries of previously undetected beneficial and adverse drug effects. Therefore, using pharmacoepide- miology studies in post-marketing pharmacovigilance to detect drug safety signals, which shall supports more regulation decisions of medicines, has been increasingly recognized(5-7). Other applications of pharmacoepidemi- ology studies have also been emphasized, which include