Database	Period of search	Search strategy
The Cochrane Hepato‐Biliary Group Controlled Trials Register	July 2008	(adenoma OR adenomas OR polyp OR polyps) AND (gallbladder OR gall‐bladder OR "gall bladder") AND (cholecystecto* OR colecystecto* )
Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library	Issue 2, 2008	#1 MeSH descriptor Polyps explode all trees #2 MeSH descriptor Adenoma explode all trees #3 MeSH descriptor Adenomatous Polyps explode all trees #4 adenoma OR adenomas OR polyp OR polyps #5 (#1 OR #2 OR #3 OR #4) #6 MeSH descriptor Gallbladder explode all trees #7 MeSH descriptor Gallbladder Neoplasms explode all trees #8 MeSH descriptor Gallbladder Diseases explode all trees #9 gallbladder OR gall‐bladder OR "gall bladder" #10 (#6 OR #7 OR #8 OR #9) #11 MeSH descriptor Cholecystectomy explode all trees #12 cholecystecto* OR colecystecto* #13 (#11 OR #12) #14 (#5 AND #10 AND #13)
MEDLINE (PubMed)	1951 to July 2008	("Polyps"[MeSH] OR "Adenoma"[MeSH] OR "Adenomatous Polyps"[MeSH] OR adenoma OR adenomas OR polyp OR polyps) AND (gallbladder OR gall‐bladder OR “gall bladder” OR "Gallbladder"[MeSH] OR "Gallbladder Neoplasms"[MeSH] OR "Gallbladder Diseases"[MeSH]) AND (cholecystecto* OR colecystecto* OR “cholecystectomy"[MeSH]) AND ((randomized controlled trial [pt] OR controlled clinical trial [pt] OR randomized [tiab] OR placebo [tiab] OR drug therapy [sh] OR randomly [tiab] OR trial [tiab] OR groups [tiab]) AND humans [mh])
EMBASE (Dialog Datastar)	1974 to July 2008	1 ADENOMA#.W..DE. OR POLYP#.W..DE. OR adenoma OR adenomas OR polyp OR polyps 2 gallbladder OR gall‐bladder OR gall ADJ bladder OR GALLBLADDER‐DISEASE#.DE. OR GALLBLADDER‐TUMOR#.DE. OR GALLBLADDER#.W..DE. 3 CHOLECYSTECTOMY#.W..DE. OR cholecystecto$ OR colecystecto$ 4 1 AND 2 AND 3 5 RANDOM$ OR FACTORIAL$ OR CROSSOVER$ OR CROSS ADJ OVER$ OR PLACEBO$ OR DOUBL$ ADJ BLIND$ OR SINGL$ ADJ BLIND$ OR ASSIGN$ OR ALLOCAT$ OR VOLUNTEER$ OR CROSSOVER‐PROCEDURE#.MJ. OR DOUBLE‐BLIND‐PROCEDURE#.DE. OR SINGLE‐BLIND‐PROCEDURE#.DE. OR RANDOMIZED‐CONTROLLED‐TRIAL#.DE. 6 4 AND 5
Science Citation Index Expanded (http://portal.isiknowledge.com/portal.cgi?DestApp=WOS&Func=Frame)	1987 to July 2008	#1 TS=(adenoma OR adenomas OR polyp OR polyps) #2 TS=(gallbladder OR gall‐bladder OR "gall bladder") #3 TS=(cholecystecto* OR colecystecto*) #4 TS=(random* OR blind* OR placebo* OR meta‐analysis) #5 #1 AND #2 AND #3 AND #4