Inclusion Criteria:

1. 18 years old or older
2. Able to provide written informed consent or have a legal surrogate who can provide written consent
3. Presenting with evidence of severe ongoing hematochezia (i.e. passage of red blood or clots per rectum witnessed by a health care provider) and have a decrease in hemoglobin from baseline of 2 or more grams and/or transfusion of 1 or more units of red blood cells for resuscitation with either outpatient or inpatient start of severe hematochezia.

Exclusion Criteria:

1. Uncooperative, unable to give written informed consent personally or through a legal surrogate, or refuse to participate

2. Contraindication to undergo capsule endoscopy due to:

   1. Documented or suspected bowel obstruction (partial or complete)
   2. Anatomical GI abnormalities such as strictures of the foregut or small bowel
   3. Inability to swallow the capsule
   4. Presence of cardiac pacemakers or other implanted electromedical devices

3. American Society of Anesthesiology (ASA) class V (very severe co-morbidities and very poor prognosis for surgery or similar procedures)

4. Very severe GI bleeding with shock not responsive to IV fluid resuscitation and/or transfusions and IV medications to raise the systolic blood pressure

5. History of recent hematemesis (within 30 days), positive nasogastric, or orogastric (OG) aspirate suggesting an upper GI bleed

6. Presenting with recurrent hematochezia that has been previously diagnosed as anorectal bleeding