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.