Theoretically, aspirin and drugs like ibuprofen can inhibit blood clotting and make the risk of bleeding higher. You would think this would be important if you are going to have a biopsy taken or polyp removed. But in practice, this does not seem to be a too much of a problem. Your doctor will help you make that decision.
Most doctors no longer routinely ask their patients to stop aspirin products before a scope test. But, if you& are on a daily aspirin or ibuprofen regimen and wish to stop it before your exam, you must stop at least a week before your test to get the medication out of your system.
Caution: If you are taking a daily aspirin to prevent a stroke or heart attack, don't stop it without your doctor's approval. Of course, if you have any bleeding tendencies, let your doctor know.