Overview: Comprehensive and carefully constructed strategies are required when conducting searches for adverse effects data

Objective: Methodological research has been undertaken to investigate the many challenges in searching for adverse effects data. It is imperative that the search approach adopted in systematic reviews is based on the best available evidence. We provide a detailed summary of the results and implications of the current evidence base to assist future searches for adverse effects. Study Design and Setting: This paper is a narrative review from the authors of the Cochrane Handbook chapter on adverse effects. Results: The specified search strategy must be based on the PICO (Population, Intervention, Comparator, Outcome(s)) format for question formulation and appropriate study designs for adverse effects data. Search filters and suggested search terms are available for the adverse effects of drug, medical devices and surgical interventions. The use of generic adverse effects terms (such as harms, and complications) as textwords and indexing terms and specific adverse effects terms (such as rash and wound infection) are warranted. Searching databases beyond MEDLINE has proven useful, as well as the use of non-database sources. Conclusion: This paper provides the most up to date evidence-based guidance in identifying adverse effects data in the literature. It will support searchers and researchers evaluating the potential for harm of medical interventions in systematic reviews