Version July 2025
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Why does cancer treatment cause nausea and vomiting? —
Nausea is the feeling that you might throw up. Vomiting is actually throwing up. Both are common side effects of a cancer treatment called chemotherapy. These are medicines that kill cancer cells.
Not everyone who gets chemotherapy will have nausea and vomiting. Your doctor will tell you how likely it is you will have these symptoms and how severe they might be.
When people have nausea and vomiting after chemotherapy, they usually feel better within 1 to 2 days. But some people have symptoms up to 3 to 4 days. This depends on the type of chemotherapy medicines, the dose, and the treatment schedule.
Another type of cancer treatment, called radiation therapy, can also cause nausea and vomiting. Not everyone who gets radiation therapy will have nausea and vomiting. It depends on the part of the body being treated, the dose of radiation, and whether the person gets chemotherapy at the same time.
Can nausea and vomiting be prevented? —
Yes. If your chemotherapy is the type that is likely to cause nausea and vomiting, your doctor will give you medicines just before your treatment. These medicines can prevent nausea and vomiting. There are different medicines your doctor can use, and they come in different forms. They can come as a pill, skin patch, or a tablet that melts under the tongue. Or they can go into your vein through a thin tube called an "IV." You might get 1 or more medicines.
If you are likely to have nausea and vomiting for a few days after chemotherapy, you might also take some of these medicines at home for 2 to 4 days after treatment.
If your radiation therapy can cause nausea and vomiting, your doctor will prescribe medicine to take before each day's treatment.
How can I manage my nausea and vomiting? —
You should do the following:
●Take all your medicines as instructed, even if you feel fine. The best way to manage nausea and vomiting is to prevent it from happening.
●Drink plenty of fluids to stay hydrated.
●Eat 5 or 6 small meals during the day after chemotherapy instead of 3 big ones, especially if you have nausea.
●Learn how much to eat or drink before your cancer treatment. Some people feel better when they eat or drink a small amount before. Other people feel better if they don't have any food or drink before.
●If you have nausea, avoid foods that are spicy, greasy, or "heavy." Instead, eat foods that are bland, such as crackers, rice, and toast. Other good choices are soup broths, clear soda, tea, bananas, chicken (broiled or baked, not fried), oatmeal, yogurt (plain or vanilla), plain pasta, and ice pops.
●Wait at least 1 hour after treatment before eating and drinking.
●Eat and drink slowly.
●Ask someone else to cook your food, if the smell of food bothers you.
●Try drinking ginger ale or taking over-the-counter ginger supplements to settle your stomach. Experts don't all agree on whether this works, but some people find it helpful.
●Ask your doctor about an alternative treatment called acupuncture.
●Some people wonder about trying marijuana (or other forms of cannabis, like CBD oil) to help with nausea or vomiting. But studies have not compared it with newer prescription medicines that are used to prevent nausea and vomiting caused by cancer therapy. For this reason, doctors do not recommend it. The active ingredient in marijuana, dronabinol, is available as a pill for certain situations. Your doctor might suggest this if other treatments have not worked for you.
When should I call my doctor or nurse? —
Call for advice if you:
●Cannot keep any food or drink down
●Vomit up your nausea and vomiting medicines
Patient education: Nausea and vomiting in adults (The Basics)
Patient education: Chemotherapy (The Basics)
Patient education: External beam radiation therapy (The Basics)
Patient education: Managing loss of appetite and weight loss with cancer (The Basics)
Patient education: Complementary and alternative medicine (The Basics)
