Concerns about missing cases of bowel cancer could be putting people at risk of bowel perforation or major bleeding, they said.
Bowel polyps are small growths on the inner lining of the colon or rectum and affect 15% to 20% of the population. They can eventually turn into cancer if left untreated.
For this reason, they are generally removed in those having a colonoscopy.
Professor Geir Hoff and colleagues in Norway said more evidence was needed so that the risks of removing harmless polyps did not outweigh the benefits.
Less than 5% of adenomas, the most common polyps found, develop into bowel cancer, suggesting 95% of procedures may be exposing patients to unnecessary risks, they went on.
Mark Flannagan, chief executive of the charity Beating Bowel Cancer, said: "Whilst this study raises reasonable questions about the need to remove all polyps which are found, much more research needs to be done."