Nausea and Vomiting

Approved by the Cancer.Net Editorial Board, 07/2020

Nausea and vomiting are common and sometimes serious side effects of cancer treatment. Chemotherapy, radiation therapy, and other cancer treatments can cause nausea and vomiting.

Nausea is feeling queasy, sick to your stomach, or like you might throw up. Vomiting is throwing up the food and liquid in your stomach.

These symptoms can be mild or severe. Mild nausea and vomiting can be uncomfortable but does not usually harm your health. Vomiting a lot can cause other health problems, such as dehydration, weight loss, and fatigue. Always tell your doctor if you feel nausea or experience vomiting, even if it is mild. There are many anti-nausea treatments available today. You might take 1 medicine or a combination of medicines to help prevent or reduce these side effects.  

It is important that your nausea and vomiting are controlled and managed. If they aren’t, these problems can affect your daily life, mental health, physical health, and even delay treatment. Relieving side effects, also called palliative care or supportive care, is an important part of cancer care and treatment. 

What causes nausea and vomiting?

You may have heard that cancer treatment always causes nausea and vomiting. This is not true. Only some treatments will cause you to have an upset stomach or throw up. Some people are also more likely to experience nausea and vomiting than others.

When you have cancer, the causes of nausea and vomiting can include:

Chemotherapy. Nausea and vomiting are common side effects of certain chemotherapy drugs. This may be called chemotherapy-induced nausea and vomiting (CINV) by your health care team.  And, a higher dosage of chemotherapy can make your side effects worse. 

Radiation therapy. Radiation therapy to large areas of the body and specifically to the gastrointestinal (GI) tract, liver, or brain can cause nausea and vomiting. A higher dosage of radiation therapy is also more likely to cause these symptoms.

Other medications used in cancer care. Other drugs used to treat cancer, including targeted therapy and immunotherapy, can cause nausea and vomiting. Some medications to help with side effects can also cause nausea and vomiting. For instance, pain medications commonly cause stomach problems. 

In general, some medicines are more likely to cause nausea and vomiting than others. The medical term “emetic” means something that causes vomiting. You can learn about different emetic oral and intravenous (IV) medicines that may cause nausea and vomiting. Please note that these PDF links take you to a different ASCO website.

Certain cancers. Brain tumors, liver tumors, and GI tumors are more likely to cause nausea and vomiting.

Dehydration, infection, pain, and other problems. Nausea and vomiting may be caused by other symptoms and side effects. It may also be caused by other diseases, like kidney disease. 

Anxiety. Nausea and vomiting can be caused by the stress and anxiety caused by cancer and its treatment.

You may be more likely to experience nausea and vomiting during your cancer treatment if you are a woman or if you are younger than 50 years old. You are also more likely to experience these side effects if you:  

  • Have a history of morning sickness during pregnancy

  • Often experience motion sickness

  • Have a history of anxiety

  • Experienced nausea and vomiting during previous chemotherapy or radiation treatments

Talk with your health care team about each medicine prescribed for you and its risk of causing nausea and vomiting. Ask if you could be at a higher risk for nausea and vomiting. And, let them know regularly how you are feeling or about side effects you are experiencing, so that they can find ways to help you feel better.

How are nausea and vomiting treated and prevented during cancer care?

If you have nausea and vomiting during your cancer care, your doctor can prescribe medicine to help relieve your symptoms. Your doctor may also prescribe medicine to prevent nausea and vomiting. These types of medicines are called “antiemetics.”

ASCO recommends the following options, based on the level of risk that a specific anti-cancer drug will cause nausea and vomiting:

High risk of nausea and vomiting. Some types of chemotherapy nearly always cause nausea and vomiting if given without antiemetics. The recommended options for preventing vomiting from these treatments are listed below.

Adults usually receive a combination of 4 medicines to prevent vomiting:

  • An NK1 receptor antagonist

  • A 5-HT3 receptor antagonist

  • Dexamethasone (available as a generic drug)

  • Olanzapine (Zyprexa)

Adults treated with high-dose chemotherapy for a bone marrow/stem cell transplant should receive a combination of 3 medicines to prevent vomiting, with the option of adding a fourth, olanzapine: 

  • An NK1 receptor antagonist 

  • A 5-HT3 receptor antagonist 

  • Dexamethasone (available as a generic drug) 

  • Olanzapine (Zyprexa) 

Children usually receive a combination of 2 or 3 medicines to prevent vomiting. These may include:

  • A 5-HT3 receptor antagonist

  • An NK1 receptor antagonist

  • Dexamethasone

Moderate risk of nausea and vomiting. Adults usually receive a combination of 2 or 3 medicines to prevent vomiting:

  • An NK1 receptor antagonist in certain instances

  • A 5-HT3 receptor antagonist

  • Dexamethasone

Children usually receive a combination of 2 medicines to prevent vomiting. These may include:

  • A 5-HT3 receptor antagonist

  • Dexamethasone

  • Aprepitant (Cinvanti) or fosaprepitant (Emend), if a child cannot receive dexamethasone

Low risk of nausea and vomiting. Adults usually receive 1 of the following:

  • A 5-HT3 receptor antagonist

  • Dexamethasone

Children usually receive 1 of the following:

  • Odansetron (Zofran, Zuplenz)

  • Granisetron (Sancuso, Sustol)

Minimal risk of nausea and vomiting. Adults and children usually do not receive medicine when the risk is very low.

When your cancer is treated with radiation therapy, your doctor may prescribe different medications depending on where on the body you will receive radiation therapy and how likely it is to cause nausea and vomiting. ASCO recommends the following options:

High risk of nausea and vomiting. Radiation therapy directed at the entire body nearly always causes nausea and vomiting if given without antiemetics. To prevent vomiting, people usually receive a combination of 2 drugs:

  • A 5-HT3 receptor antagonist

  • Dexamethasone

Moderate risk of nausea and vomiting. People receiving radiation therapy with a moderate risk of nausea and vomiting usually receive a 5-HT3 receptor antagonist. This is sometimes combined with dexamethasone.

Low risk of nausea and vomiting. People receiving radiation therapy that is less likely to cause nausea and vomiting may receive antiemetics after treatment if they feel nauseated or vomit.

  • For those who received radiation therapy to the brain, dexamethasone is generally used if nausea or vomiting develops.

  • For those who received radiation therapy to the head and neck, chest, or pelvis, a 5-HT3 receptor antagonist, dexamethasone, or a dopamine receptor antagonist are options if nausea or vomiting develops.

Minimal risk of nausea and vomiting. People usually receive a 5-HT3 receptor antagonist, dexamethasone, or a dopamine receptor antagonist if nausea or vomiting develops.

People receiving radiation therapy along with chemotherapy usually also receive the antiemetics recommended for chemotherapy or targeted therapy, unless they are receiving radiation therapy with a higher risk of causing nausea and vomiting.

Learn more about ASCO’s guidelines on preventing nausea and vomiting from chemotherapy or radiation therapy with medicine. Please note that this link takes you to a separate ASCO website.

What if I feel nauseated or throw up before treatment?

You may start feeling sick before each treatment appointment, especially if your treatments have been making you nauseous. This is called anticipatory nausea and vomiting. Tell your doctor if this happens to you. You can take anti-nausea medication or try other ways of making your nausea feel better, such as relaxation techniques. Sometimes an anti-anxiety medication called lorazepam (Ativan) is also recommended.

Are there other ways to reduce nausea and vomiting?

There are ways to help relieve nausea and vomiting that do not use medicines. These include:

  • Changing what foods or how you eat, such as eating smaller meals more often, and staying hydrated. An oncology dietitian can help with this.

  • Distracting yourself and doing things that relax you

  • Doing meditation or focusing your mind on a positive picture, scene, or idea

  • Acupressure and acupuncture

Some herbal products can also help nausea, such as ginger. Always talk to your doctor before using any alternative or complementary treatment. If your doctor prescribes anti-nausea medicines, do not stop taking them or use something else without asking your doctor.

You might be curious about using marijuana to relieve nausea and vomiting. Doctors do not yet have enough evidence to recommend it as a treatment. But you can take medicines called dronabinol (Marinol or Syndros) and nabilone (Cesamet). They are synthetic forms of cannabis, and the U.S. Food and Drug Administration has approved them as medicines. You might try these if other anti-nausea medicines do not work well for you.

Questions to ask your health care team

Consider asking your health care team these questions about nausea and vomiting before you start cancer treatment.

  • Is this cancer treatment likely to cause nausea and vomiting? If so, when could those side effects start?

  • Is there a way to prevent these side effects of cancer treatment?

  • Who should I tell if I start experiencing nausea or vomiting?

  • How can my nausea be relieved if it starts?

  • Do you think certain anti-nausea medicines will work better for me? Why?

  • What are signs that nausea and vomiting are affecting my hydration or nutrition?

  • Should I tell you right away if this antiemetic treatment doesn’t relieve my symptoms?

  • Should I keep track of my nausea and vomiting? If so, how should I track my symptoms?

  • What should I do if I’m very anxious about nausea and vomiting?

  • Do these recommended antiemetic medications have any side effects I should know about?

  • Who can I talk to if I have trouble paying for the medicine or need one that costs less?

During your treatment and recovery, please tell your doctor or someone else on your health care team if you have nausea and vomiting so that they can treat it as soon as possible. If they know how you are feeling, they can find ways to relieve or manage your side effects to help you feel more comfortable, continue your treatment as planned, and potentially keep side effects from worsening.

Related Resources

Side Effects of Chemotherapy

Side Effects of Radiation Therapy

Fear of Treatment Side Effects

Nutrition Recommendations During and After Cancer Treatment

More Information

American Cancer Society: Nausea and Vomiting

CancerCare: Nausea and Vomiting

National Cancer Institute: Nausea and Vomiting

ASCO answers; Nausea and VomitingDownload ASCO's free 1-page (front and back) fact sheet on Nausea and Vomiting as a printable PDF. This introduction to preventing and managing nausea and vomiting includes possible causes and risk factors, prevention and treatment options, words to know, and questions to ask the health care team. Order printed copies of the fact sheet in English from the ASCO Store.