Assessment of safety of newly marketed drugs is an important public health issue. Once the drug is in the market, clinicians and/or health professionals are responsible for recognizing and reporting suspected side effects known as adverse drug reaction (ADR). Such reports are collected in a so-called spontaneous reporting (SR) system. The primary purpose of spontaneous ADR reporting is to provide early warnings or suspicions, which have not been recognized prior to marketing of a drug because of limitations of clinical trials. We shall discuss the existing work to analyze the SR database and their drawbacks and also suggest methodologies to tackle these drawbacks by defining a source population and considering the problem of under-reporting, with the help of supplementary data. Unbiased estimate of population odds-ratio has been obtained and the corresponding asymptotic results are derived. Copyright © 2011 John Wiley & Sons, Ltd.