Throwing up blood, known medically as hematemesis, signals bleeding somewhere in your upper digestive tract: the esophagus, stomach, or the first stretch of the small intestine. The most common causes are stomach ulcers, tears in the esophageal lining, irritation from alcohol or medications, and swollen veins in the esophagus linked to liver disease. Even with advances in treatment, upper GI bleeding still carries a mortality rate of 8 to 15 percent, which is why any amount of blood in vomit warrants urgent medical attention.
What the Blood Looks Like Matters
The color of blood in your vomit tells you something important about where and how fast the bleeding is happening. Bright red blood is fresh, meaning the bleeding is active and likely coming from the esophagus or upper stomach. This is the more alarming presentation and often indicates rapid blood loss.
Dark red, brown, or black material that resembles coffee grounds is blood that has been sitting in your digestive tract long enough to partially clot and dry. By the time your body triggers the vomiting reflex, that blood has already begun to congeal and darken. Coffee-ground vomit suggests the bleeding has slowed or temporarily stopped, but it still points to a source that needs investigation. Either appearance is a reason to get emergency care.
Stomach Ulcers and Erosion
Peptic ulcers are open sores in the lining of the stomach or the upper part of the small intestine. They develop when the protective mucus layer wears down and digestive acid eats into the tissue. The two primary drivers are infection with the bacterium H. pylori and chronic use of pain relievers like aspirin, ibuprofen, and naproxen. When an ulcer erodes into a blood vessel, the bleeding can range from a slow ooze (producing coffee-ground vomit) to a sudden, heavy bleed (producing bright red blood).
Erosive gastritis, a related condition, involves widespread inflammation and shallow damage across the stomach lining rather than a single deep sore. Heavy alcohol use is a classic trigger. Alcohol gradually irritates and erodes the stomach lining, and over time this can cause bleeding significant enough to appear in vomit or stool.
Pain Medications and Bleeding Risk
NSAIDs (nonsteroidal anti-inflammatory drugs) and aspirin have overtaken H. pylori as the leading cause of upper GI damage in Western countries. These medications work by suppressing the same chemicals that help protect your stomach lining, so regular use leaves the tissue vulnerable to acid. The risk is dose-dependent and increases steadily with longer use. Taking higher doses, combining multiple pain relievers, or using them daily for chronic pain all raise the odds further.
Not all NSAIDs carry identical risk. Ibuprofen and celecoxib sit at the lower end, while indomethacin, naproxen, and piroxicam carry substantially higher risks of upper GI complications. Even low-dose aspirin, commonly taken for heart protection, contributes: GI bleeding accounted for 72 percent of aspirin-related hospital admissions in one large analysis. If you take these medications regularly and notice dark stools or any blood in your vomit, that connection is worth flagging to a doctor immediately.
Tears in the Esophagus
A Mallory-Weiss tear is a split in the inner lining of the esophagus, right at or near the point where it meets the stomach. These tears happen when sudden pressure in the abdomen forces stomach contents upward against the esophageal wall. The most common trigger is forceful or prolonged vomiting, which is why these tears frequently show up after binge drinking episodes, severe food poisoning, or persistent retching from any cause.
Other triggers include heavy lifting or straining, prolonged bouts of coughing, and trauma to the chest or abdomen. Most Mallory-Weiss tears heal on their own within a few days once the vomiting or straining stops, but some bleed enough to require treatment during an endoscopy.
Esophageal Varices and Liver Disease
This is one of the most dangerous causes of vomiting blood. When the liver is scarred from cirrhosis, blood flow through it gets blocked. Pressure builds in the portal vein, the major vessel that feeds the liver, and blood is forced to reroute through smaller veins that weren’t built to handle that volume. The veins in the lower esophagus are a common detour. They balloon outward under the strain, becoming fragile, thin-walled pouches called varices.
When a varix ruptures, the bleeding can be massive and life-threatening. The blood is typically bright red and comes in large amounts. This is a medical emergency. People with known liver disease, heavy long-term alcohol use, or hepatitis are at the highest risk. In many cases, doctors screen for varices before they burst and offer preventive treatment to reduce the pressure.
Less Common Causes
Several other conditions can produce blood in vomit, though they account for a smaller share of cases:
- Esophagitis: Chronic acid reflux can inflame and erode the esophageal lining enough to cause bleeding, particularly if left untreated for months or years.
- Stomach or esophageal cancers: Tumors in the upper digestive tract can erode into blood vessels. Bleeding may be gradual, showing up as coffee-ground vomit, unexplained weight loss, or difficulty swallowing.
- Swallowed blood: A severe nosebleed or dental procedure can send enough blood into the stomach to trigger vomiting. This is alarming but not a sign of internal disease.
- Blood-thinning medications: Anticoagulants don’t cause bleeding on their own, but they make any existing source bleed more freely and for longer.
Warning Signs of Severe Blood Loss
The bleeding itself is the primary concern, but the real danger comes when enough blood is lost to affect circulation. If bleeding starts suddenly and worsens quickly, you can go into shock. The signs include dizziness or fainting, a rapid pulse, and a noticeable drop in blood pressure. Skin may feel cold or clammy. These symptoms mean the body is struggling to maintain blood flow to vital organs, and emergency treatment is needed immediately.
Even without those dramatic signs, lighter symptoms deserve attention. Ongoing fatigue, dark or tarry stools, and repeated episodes of coffee-ground vomit all suggest chronic bleeding that can lead to anemia over time.
How Doctors Find the Source
The standard tool for diagnosing upper GI bleeding is an upper endoscopy. A thin, flexible tube with a tiny camera on the end is passed down the throat and into the esophagus, stomach, and upper small intestine. This lets the doctor visually inspect the lining and pinpoint exactly where the blood is coming from.
The useful part about endoscopy is that it’s often both diagnostic and therapeutic in the same session. If the doctor spots a bleeding ulcer, a torn vessel, or a ruptured varix, they can frequently treat it on the spot, using techniques to seal the bleeding site. If endoscopy doesn’t resolve the problem, other interventional approaches are available, but the scope is the first step in the vast majority of cases. You’re typically sedated for the procedure and won’t feel it, though your throat may be sore afterward.