BACKGROUND The incidence of impacted wisdom teeth is high, with some 72% of Swedish people aged 20 to 30 years having at least one impacted third molar. Impacted wisdom teeth occur because of a lack of space, obstruction, or abnormal position, and can cause inflammatory dental disease manifested by pain and swelling of infected teeth and may destroy adjacent teeth and bone. METHODS We conducted a systematic review and aimed to answer the following clinical questions: Should asymptomatic and disease-free impacted wisdom teeth be removed prophylactically? What are the effects of different surgical methods of removing impacted wisdom teeth? We searched: Medline, Embase, The Cochrane Library, and other important databases up to July 2009 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA). We performed a GRADE evaluation of the quality of evidence for interventions. RESULTS We found 25 systematic reviews, RCTs, or observational studies that met our inclusion criteria. CONCLUSIONS In this systematic review we present information relating to the effectiveness and safety of the following interventions: prophylactic extraction, active surveillance, and different surgical methods of removing impacted wisdom teeth.