Gastrointestinal bleeding: signs, causes and what to do
Seeing blood in vomit, stool, or on the toilet paper is scary. Gastrointestinal (GI) bleeding means blood is coming from somewhere in your digestive tract — from the esophagus down to the rectum. Some bleeds are small and easy to treat; others need immediate hospital care. This guide helps you spot the red flags, understand likely causes, and know what to expect from tests and treatments.
How bleeding looks and what it means
Upper GI bleeding (stomach, esophagus, first part of the small intestine) often shows up as bright red vomit or dark, tarry stools called melena. Dark, sticky stool usually means the blood was in the gut for a while. Lower GI bleeding (colon, rectum) usually shows fresh red blood in or on stool — sometimes mixed with toilet paper or streaked on the surface.
Other signs include feeling faint, fast heartbeat, low blood pressure, pale skin, or sudden weakness. If you have any of these with visible bleeding, treat it as an emergency.
Common causes and simple explanations
There are many reasons for GI bleeding. Here are the ones you’re most likely to see:
- Peptic ulcers: Sores in the stomach or small intestine that can bleed, often linked to NSAID use or H. pylori infection.
- Gastritis and esophagitis: Inflammation from alcohol, pills, or infection that can cause small bleeds.
- Varices: Enlarged veins in the esophagus from liver disease. These can bleed heavily and suddenly.
- Hemorrhoids and anal fissures: Common, painful, and usually cause bright red blood on toilet paper.
- Diverticulosis and colon polyps: Small pouches or growths in the colon that can bleed, especially in older adults.
- Cancer: Tumors in the stomach or colon may bleed slowly and be hard to notice until they cause anemia.
- Medications: Blood thinners (like warfarin or newer anticoagulants) and NSAIDs raise bleeding risk. If you take these, talk with your doctor about signs to watch for.
How doctors find the source: expect blood tests to check your hemoglobin and clotting. Endoscopy (a camera down your throat) looks for upper GI sources. Colonoscopy checks the colon. Sometimes CT scans, tagged red blood cell scans, or angiography are used if bleeding is heavy and the source is hard to find.
Treatment depends on cause and severity. Minor bleeds may stop on their own or with medicine like proton pump inhibitors for ulcers. Endoscopy can treat many bleeds right away — doctors can clip, inject, or cauterize the bleeding spot. Severe cases may need blood transfusion, interventional radiology, or rarely surgery. For variceal bleeding, doctors use special drugs and banding procedures.
What you can do now: don’t ignore visible blood. If bleeding is heavy, you feel faint, short of breath, or very weak, call emergency services. For non-urgent concerns, contact your GP — they may order tests or refer you to a specialist. Avoid NSAIDs and alcohol until you know the cause, and tell your providers about any blood thinners you take.
Knowing the signs and acting quickly makes a big difference. If you’re unsure, err on the side of caution and get evaluated right away.
