Nausea and Vomiting in Colon Cancer

Doctors Will Consider A Bowel Obstruction From a Tumor

Young woman holding ginger biscuit eaten to help prevent nausea
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Nausea and vomiting may occur for a number of reasons including motion sickness, a medication side effect, migraines, pregnancy, food allergies, an inner ear problem, or a slew of common gastrointestinal infections.

But, sometimes, nausea and vomiting are symptoms of something more serious, such as colon cancer.

How Colon Cancer Causes Nausea and Vomiting

When nausea and vomiting are symptoms of colon cancer, it's usually because a tumor is causing a bowel obstruction, usually in the proximal colon (meaning the end closer to the small intestines).

This means that the tumor (the mass of cancer cells) is physically blocking the intestines. Depending on the severity of the blockage, solids, liquids, and even gas may be prevented from passing through the colon. This can lead to painful stomach cramps, bloating, and constipation, and sometimes (but not always) nausea and/or vomiting.

A doctor can usually diagnose a bowel obstruction based on your symptoms, but a definitive diagnosis is made with a CT scan of the abdomen. Of course, other health problems may cause a bowel obstruction besides a tumor, like a hernia or ​a scar tissue from a prior surgery in the abdomen. 

As an aside, it's important to remember that nausea and vomiting may result from the cancer medications used to treat colon cancer.

Other Serious Causes of Nausea and Vomiting Besides Colon Cancer

Of course, colon cancer is not the only serious cause of nausea and vomiting. Other potential serious causes include stomach or intestinal ulcers, inflammation of abdominal organ (for example, the appendix, pancreas, gallbladder, or liver), ingestion of a dangerous substance, a kidney infection, or a heart problem.

Increased intracranial pressure from a brain tumor or a brain infection may also cause nausea and vomiting. 

This is why it's important to seek out medical attention if your nausea and vomiting is persistent or is associated with other worrisome signs or symptoms.

In addition to getting to the root cause of your nausea and vomiting, dehydration and electrolyte imbalances are another concern.

This is why it's important to get medical attention if you have been vomiting for more than 24 hours, are unable to keep fluids down for a 12-hour period, or have signs of dehydration like:

  • Increased thirst
  • Decreased skin elasticity
  • Dry mouth
  • Sunken eyes
  • Crying with no tears
  • Infrequent urination (less than every 8 hours per day)
  • Dark, yellow urine

The good news is that if you cannot keep fluids down on your own, you can receive fluids intravenously (meaning through your vein). This is a relatively simple intervention, and you will feel much better. 

Of course, if you notice blood in your vomit or a dark substance in your vomit that resembles coffee grounds, you need to seek emergent medical attention. Severe stomach pain, a headache, and stiff neck, or ingestion of a poison or toxic substance also warrant emergent medical attention.

Treating Nausea and Vomiting in Colon Cancer

If a bowel obstruction from colon cancer is the cause of your nausea and vomiting, you will need to receive care in a hospital setting. In the hospital, you will receive intravenous fluids, a nasogastric tube that decompresses your gastrointestinal tract, and a surgery consultation. Sometimes, a stent can be placed to relieve the obstruction prior to surgery or in lieu of surgery, depending on the goals of care.


A Word From Verywell

It's important to remember that the occurrence of nausea and vomiting alone, without other colon cancer symptoms, is unlikely an indication of cancer. There are lots of reasons for feeling sick and throwing up.

That being said, if nausea and vomiting are accompanied by other worrisome signs like constipation, abdominal pain or cramping, and/or abdominal distension, colon cancer could be a cause. 


National Cancer Institute. (September 2015). Nausea and Vomiting. 

National Institute of Health. (August 2015). Medical Encyclopedia: Nausea and Vomiting. 

Yeh DD, Bordeianou L. (August 2015). Overview of mechanical colorectal obstruction. In: UpToDate, Weiser M (Ed), UpToDate, Waltham, MA.