Nausea and Vomiting, ASCO's curriculum

This section has been reviewed and approved by the PLWC Editorial Board, 05/05

Nausea is the urge to vomit. Vomiting, also called emesis or throwing up, is the act of expelling the contents of the stomach through the mouth. It is a natural way for the body to rid itself of harmful substances. Nausea and vomiting are common in people receiving chemotherapy for cancer and in some people receiving radiation therapy. Many people with cancer say that they fear nausea and vomiting more than any other side effect of treatment.

Mild nausea and vomiting can be quite uncomfortable, but usually causes no serious problems. Persistent vomiting can cause dehydration, electrolyte imbalance, weight loss, depression, and avoidance of chemotherapy.


Nausea and vomiting in people with cancer may be caused by the following:

  • Chemotherapy
  • Radiation therapy, especially to the brain, spinal cord, abdomen, and pelvis. People who have received total body radiation therapy (such as before a bone marrow transplantation) are at the highest risk.
  • Cancer that has spread to the brain
  • Blocked intestines (bowel obstruction)

  • Electrolyte imbalance
  • Infections or bleeding in the gastrointestinal (stomach and intestines) system
  • Heart disease
  • Other medications

Anticipatory vomiting occurs in people who have vomited from chemotherapy before. It can happen in the time before a person knows he or she must go back to the hospital to have more chemotherapy. Acute vomiting is vomiting that takes place in the first 24 hours after treatment. Delayed vomiting may continue two or more days after treatment.

People who are at the highest risk for chemotherapy-induced nausea and vomiting include the following:

  • People who have previously vomited after cancer treatment
  • People who are prone to motion sickness
  • People who are anxious before cancer treatment
  • People under age 50, especially women

Managing nausea and vomiting

Whenever possible, it is best to prevent nausea and vomiting from starting. There are many medications available to help reduce or stop vomiting. If you are at risk, your doctor may prescribe the antiemetic medications (drugs to stop vomiting) before cancer treatment. In addition, many people find that behavioral treatments can help control nausea and vomiting. Methods such as distraction, relaxation, and positive imagery can help change the expectation and fear of nausea and vomiting.

More Information

ASCO Patient Guide: Preventing Nausea and Vomiting Caused by Cancer Treatment

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