Upper gastrointestinal (GI) bleeding originates from somewhere between the esophagus and the upper part of the small intestine. It affects roughly 80 to 150 people per 100,000 each year and carries an estimated mortality rate of 2 to 10%, depending on the cause and severity. The triggers range from common medications to chronic liver disease, and understanding what’s behind the bleeding matters because the cause largely determines how dangerous it is.
Peptic Ulcers: The Most Common Cause
Peptic ulcers have long been considered the leading cause of upper GI bleeding. These are open sores that develop on the lining of the stomach or the first section of the small intestine. Older estimates placed ulcers behind about 50% of all cases, though more recent endoscopic data from large databases suggest the number is closer to 20 to 30%. The discrepancy likely reflects changes in how ulcers are treated and how often they’re actually confirmed during examination.
Two factors drive most ulcer formation. The first is infection with the bacterium H. pylori, which weakens the protective mucus layer of the stomach lining. The second is regular use of nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen, naproxen, and aspirin. These drugs suppress the production of compounds that normally protect the stomach lining, making it vulnerable to acid damage. When an ulcer erodes into a blood vessel, the result can be anything from a slow ooze to a life-threatening hemorrhage.
Medications That Raise Bleeding Risk
NSAIDs are the most well-known offenders, but several other medication categories increase the chance of upper GI bleeding. Blood thinners (oral anticoagulants) raise the risk by about 75% compared to non-users. Clopidogrel, a drug commonly prescribed after heart attacks or stent placement, increases risk by roughly 67%. High-dose oral corticosteroids, often used for inflammatory conditions, more than double the risk.
The danger compounds when these drugs are combined. Someone taking low-dose aspirin alongside an anticoagulant or corticosteroid faces a significantly higher chance of bleeding than someone on any single agent. If you take multiple medications that thin the blood or irritate the stomach lining, that cumulative effect is worth discussing with whoever prescribes them.
Esophageal Varices and Liver Disease
Varices are swollen, fragile veins that develop in the walls of the esophagus or stomach. They form because of portal hypertension, a condition where blood pressure in the vein carrying blood from the digestive organs to the liver rises too high. This is almost always caused by cirrhosis, the scarring of the liver from chronic damage due to alcohol, hepatitis, or fatty liver disease.
Here’s the mechanism: as scar tissue builds up in the liver, it blocks normal blood flow. Pressure backs up in the portal vein, and the body responds by rerouting blood through smaller, thinner-walled vessels that were never designed to handle that volume. These detour vessels, particularly at the lower end of the esophagus, balloon outward into varices. When the pressure gradient across the liver exceeds a certain threshold (roughly double the normal level), these varices become prone to rupturing. The bleeding can be sudden, massive, and fatal without emergency treatment.
About 30% of patients diagnosed with a condition called watermelon stomach (gastric antral vascular ectasia, or GAVE) also have cirrhosis, highlighting how liver disease drives multiple types of upper GI bleeding at once.
Erosive Gastritis and Esophagitis
Erosive gastritis is inflammation that wears away the stomach lining, creating shallow breaks that can bleed. The most common triggers are NSAIDs, alcohol, and physical stress on the body. In intensive care settings, critically ill patients frequently develop stress-related gastritis because reduced blood flow to the gut impairs the lining’s ability to protect itself. Patients with head injuries or severe burns face an added risk because their bodies may ramp up acid production at the same time.
Less common causes include radiation therapy, viral infections, direct trauma from medical tubes placed through the nose into the stomach, and Crohn’s disease affecting the upper digestive tract. Erosive esophagitis, where stomach acid repeatedly damages the lower esophagus (as in severe acid reflux), can also produce bleeding, though it tends to be slower and more chronic than ulcer-related hemorrhage.
Mallory-Weiss Tears
A Mallory-Weiss tear is a rip in the tissue where the esophagus meets the stomach, caused by forceful or prolonged vomiting or retching. The mechanical strain of repeated heaving literally splits the lining. Heavy alcohol use leading to vomiting has been noted in anywhere from 11 to 80% of cases in different studies, which gives a sense of how tightly this condition is linked to binge drinking. Other triggers include severe coughing, dry heaving, and straining during bowel movements.
Most Mallory-Weiss tears stop bleeding on their own and heal within a few days. But in some cases, the tear reaches a deeper blood vessel and produces significant hemorrhage that requires intervention.
Vascular Abnormalities
Some upper GI bleeding comes from structural problems with blood vessels themselves rather than from ulcers or tears. Two conditions worth knowing about fall into this category.
Dieulafoy lesions are unusually large arteries that sit just beneath the stomach lining. Unlike a normal blood vessel, which narrows as it approaches the surface, a Dieulafoy lesion stays wide. If the thin tissue covering it erodes even slightly, the exposed artery can bleed profusely. These lesions are notoriously difficult to find because they look normal between bleeding episodes.
Watermelon stomach (GAVE) involves clusters of dilated blood vessels in the lower portion of the stomach that resemble the stripes on a watermelon when seen through a scope. These fragile vessels leak blood slowly, often causing chronic anemia rather than a dramatic bleed. Women make up about 71% of cases, and the average age at diagnosis is in the late 60s to early 70s. The condition is associated with connective tissue disorders like scleroderma, chronic kidney failure, and pernicious anemia. GAVE accounts for roughly 4% of non-variceal upper GI bleeding.
How Symptoms Point to the Source
The way bleeding shows up offers clues about where it’s coming from and how fast it’s happening. Vomiting bright red blood typically signals active bleeding from an ulcer, a variceal rupture, or a vascular lesion. Vomiting dark, grainy material that looks like coffee grounds means the bleeding has slowed or stopped, and stomach acid has had time to break down the blood.
Black, tarry stools (melena) are the hallmark of upper GI bleeding. It takes roughly 100 to 200 mL of blood in the upper digestive tract to produce melena, and the dark color persists for several days after bleeding has actually stopped. This means tarry stools don’t always indicate ongoing hemorrhage, but they do confirm that a significant amount of blood passed through the system recently. Bright red blood in the stool, by contrast, usually points to a lower GI source, though a very fast upper GI bleed can occasionally produce it too.
Who Is Most at Risk
Age is a major factor. Readmission data shows the average patient hospitalized for upper GI bleeding is in their late 60s. Older adults are more likely to be on NSAIDs, blood thinners, or multiple medications that interact, and their stomach lining is thinner and more vulnerable to begin with.
People with cirrhosis carry disproportionate risk. In hospital data, patients with liver disease who were readmitted after an initial bleeding episode had longer stays, higher costs, and worse outcomes. Cirrhosis not only creates varices but also impairs the blood’s ability to clot, turning what might be a minor bleed in a healthy person into a serious event.
Other groups at elevated risk include heavy drinkers, people with chronic kidney failure, those with a prior bleeding episode (about half of 30-day hospital readmissions for upper GI bleeding were due to recurrent bleeding), and anyone with an active H. pylori infection who hasn’t been treated for it.