Endoscopic Evaluation of Lower Gastrointestinal Bleeding (GIB) in Patients Presenting With Melena

Consecutive patients with a clinical diagnosis of upper gastrointestinal bleeding will be enrolled if they meet all of the following criteria: 1. Presence of melena or melena concomitant with PR bleeding; 2. Gastroscopic findings not accountable for the upper GI bleeding including: (i) clean base ulcers /erosions (refer to User Groups below) without high-risk stigmata, fresh or altered blood but can have grade A or B esophagitis concomitantly ; and (ii) meet the criteria of either the User groups or Non-user group as below User Groups Definition: Patients who used any dose of NSAIDs or aspirin via oral or systemic (intramuscular, Per rectal) route within 2 weeks prior to the onset of upper GI bleeding NSAID group: Clean base gastric or duodenal ulcer is required (i.e., patients with normal finding or erosions alone on endoscopy will not be eligible) Aspirin group: Either an ulcer or multiple (\>5) erosions found on endoscopy Non-user group Definition : 1. No continuous use of NSAIDs or aspirin for more than 1 week within the past 3 Months and patients who had not been exposed to NSAIDs, aspirin, or unknown drugs ≥ 4 weeks prior to GI bleed; 2. Clean base gastric or duodenal ulcer is required (i.e., patients with normal finding or erosions alone on OGD will not be eligible) 3. Age ³18; 4. Willing to meet the capsule endoscopy procedure requirements, and have provided written informed consent prior to admission to this study. 5. Concomitant clean base GU and DU can be recruited Exclusion criteria The presence of any of the following will exclude a subject from study enrollment: 1. Hematemesis as the presenting symptom; 2. Gastroscopic findings accountable for the bleeding episode (i.e., presence of blood in the stomach, ulcers showing high-risk bleeding stigmata, bleeding gastroesophageal varices, Mallory-Weiss tear showing bleeding stigmata, portohypertensive gastropathy); 3. Gastroscopic findings are normal. 4. Uncontrolled bleeding requiring emergency surgery or mesenteric angiography; 5. Has cardiac pacemaker or other electromedical implant; 6. Is expected to undergo MRI examination or be in the vicinity of powerful electromagnetic fields between ingesting the capsule and its excretion; 7. Active malignancy or history of a malignancy within 5 years prior to enrollment; 8. Previous gastric surgery; 9. Known or suspected complete or partial stenosis of the small intestine; 10. Established delayed gastric emptying or diabetic gastroparesis; 11. Known inflammatory bowel disease; 12. Use of misoprostol within the 2 weeks prior to admission; 13. Concomitant use of NSAIDs and aspirin; 14. Currently taking anticoagulants or lithium; 15. Has a swallowing disorder that precludes safe ingestion of the capsule; 16. Pregnancy; 17. History of clinically significant substance abuse, drug addiction or a history of chronic ingestion of more than two alcoholic drinks per day; 18. Any mental or physical condition, which precludes compliance with study and/or device instructions; 19. Received any investigational medication within 30 days prior to the treatment period; 20. Currently participating in another clinical study that may affect the results of this study. 21. Ulcer \> 2cm 22. clean base ulcer with grade C or D esophagitis