What is hematemesis? Vomiting blood, explained
4 minute read | Published March 14, 2025
Medically Reviewed | Last reviewed by Jaffer Ajani, M.D. on March 14, 2025
Hematemesis is the scientific term for vomiting blood. But it’s not the same thing as hemoptysis, which is coughing up blood. The difference between these terms lies in the blood’s source.
- Hematemesis comes from somewhere along the digestive tract.
- Hemoptysis originates in the lungs or the airway.
So, what conditions other than cancer can cause this alarming symptom? And when should you see a doctor about it? We asked Jaffer Ajani, M.D., a medical oncologist who specializes in gastrointestinal cancers. Here’s what he had to say.
Why does hematemesis even happen?
Hematemesis can occur for many different reasons. Only some of them relate to cancer. To understand why, though, you need to know a little more about the digestive tract.
The entire inner surface of your gastrointestinal (GI) tract is covered by a layer of endothelial cells. This acts as a membrane that protects all the structures beneath it, including nerves and blood vessels. The endothelium shields hundreds of blood vessels. So, if you have a breach there, it can cause significant bleeding. And, if your stomach fills up with blood, that can cause vomiting.
What are the most common causes of hematemesis?
Benign stomach ulcers
Even though these are not cancerous, they can still cause significant bleeding.
Cancer
This could be stomach cancer, esophageal cancer or some other type of cancer that has grown through the walls of the GI tract.
Cirrhosis of the liver with portal hypertension
When blood that would normally pass through the liver encounters resistance due to scarring, it backs up and the vessels get very large and start protruding into the esophagus. The walls of these blood vessels are very delicate, and they can burst open if the pressure gets high enough.
Varicose veins
Most people associate varicose veins with legs, but they can also occur in the esophagus and stomach.
Accidental injury
These occur primarily in young children, who unknowingly swallow corrosive fluids. But they also sometimes happen when people see a sword-swallower or a fire-breather at the circus and then foolishly try to recreate those stunts at home.
Blood thinners
Blood thinners themselves don’t cause spontaneous bleeding. But if you have a small breach in the endothelium already, a blood thinner can make it start bleeding, even if it never did before. We don’t recommend that anyone run out and get on blood thinners for this reason, but that’s actually how we diagnose a lot of our patients here with early stage stomach and esophageal cancers.
Is hematemesis ever painful?
No. But whatever’s causing it might be. The symptom itself is unpleasant but usually painless.
What does the blood generated by hematemesis actually look like?
It generally falls into one of two categories:
- Bright red blood is usually fresh, and the bleeding is occurring right now.
- Dark brown blood is usually older, and has been present in the stomach for 1-2 days.
When should you see a doctor about hematemesis?
Immediately. Any time you vomit blood, consider it an emergency. Go to the ER, especially if it’s the first time it’s ever happened. You need to see somebody about it right away.
How is hematemesis typically treated?
That depends on the degree and frequency with which it’s occurring. If it only happened once and you only brought up about a teaspoon or so, we might just monitor you. That’s particularly true if we already know you have cancer of the stomach or esophagus, since hematemesis is a common symptom of those.
But if you’re losing a lot of blood, anemia can become an issue, so we need to find a way to control it and possibly replace the blood you’ve already lost.
We prefer to treat hematemesis endoscopically — or by introducing a special scope through the mouth that can cauterize wounds. That’s the least invasive method. But if endoscopy is not an option, we have interventional radiologists at MD Anderson who can perform ablations and surgeons who can perform more complicated procedures.
Does hematemesis ever go away on its own?
Yes. Often, hematemesis will clear up by itself, especially if it’s only a modest amount. But that doesn’t mean you should ignore it. Any time you vomit blood, mention it to your care team immediately.
Request an appointment at MD Anderson online or call 1-877-515-1993.
