Stomach Problems And Cancer Treatment

Cancer treatment side effects, such as nausea, vomiting, diarrhea, and constipation, can make it difficult for your loved one to get the nutrients that his or her body needs.


Nausea, with or without vomiting, is a common side effect of surgery, chemotherapy, radiation therapy, and biological therapy. The disease itself, or other conditions unrelated to your cancer or treatment, may also cause nausea. Some people have nausea or vomiting right after treatment; others don’t have it until two or three days after a treatment. Many people never experience nausea. For those who do, nausea often goes away once the treatment is completed. Also, there are now drugs that can effectively control this side effect. These medications, called antiemetics, are often given at the beginning of a chemotherapy session to prevent nausea.

Whatever the cause, nausea can keep you from getting enough food and needed nutrients. Here are some ideas that can help:

  • Ask your doctor about antiemetics that might help you control nausea and vomiting.
  • Eat small amounts, often and slowly. Eat before you get hungry, because hunger can make feelings of nausea stronger.
  • If nausea makes certain foods unappealing, then eat more of the foods you find easier to handle.
  • Avoid eating in a room that’s stuffy, too warm, or has cooking odors that might disagree with you.
  • Drink fewer liquids with meals. Drinking liquids can cause a full, bloated feeling.
  • Slowly drink or sip liquids throughout the day. A straw may help.
  • Have foods and drinks at room temperature or cooler; hot foods may add to nausea.
  • Don’t force yourself to eat favorite foods when you feel nauseated. This may cause a permanent dislike for those foods.
  • Rest after meals, because activity may slow digestion. It’s best to rest sitting up for about an hour after meals.
  • If nausea is a problem in the morning, try eating dry toast or crackers before getting up.
  • Wear loose-fitting clothes.
  • If nausea occurs during radiation therapy or chemotherapy, avoid eating for 1 to 2 hours before treatment.
  • Try to keep track of when your nausea occurs and what causes it (specific foods, events, surroundings). If possible and if it helps, change your diet or schedule. Share the information with your doctor or nurse.

Try foods that are easy on your stomach, such as:

  • Toast, crackers, and pretzels
  • Yogurt
  • Sherbet
  • Angel food cake
  • Cream of wheat, rice, or oatmeal
  • Boiled potatoes, rice, or noodles
  • Skinned chicken that is baked or broiled, not fried
  • Canned peaches or other soft, bland fruits and vegetables
  • Clear liquids
  • Ice chips
  • Carbonated drinks

Avoid foods that:

  • Are fatty, greasy, or fried
  • Are very sweet, such as candy, cookies, or cake
  • Are spicy or hot
  • Have strong odors


Vomiting may follow nausea and may be brought on by treatment, food odors, gas in the stomach or bowel, or motion. In some people, certain associations or surroundings, such as the hospital, may cause vomiting. As with nausea, some people have vomiting right after treatment, while others don’t have it until a day or more after treatment.

If vomiting is severe or lasts for more than a day or two, contact your doctor. He or she may give you an antiemetic medication to control nausea and vomiting.

Very often, if you can control nausea, you can prevent vomiting. At times, though, you may not be able to prevent either. Relaxation exercises or meditation may help you. These usually involve deep rhythmic breathing and quiet concentration, and can be done almost anywhere. If vomiting does occur, try these suggestions to help prevent further episodes:

  • Do not eat or drink anything until you have the vomiting under control.
  • Once the vomiting is under control, try small amounts of clear liquids, such as water or bouillon. Table 2 gives you more examples of clear liquids. Begin with 1 teaspoonful every 10 minutes, gradually increasing the amount to 1 tablespoon every 20 minutes. Finally, try 2 tablespoons every 30 minutes.
  • When you are able to keep down clear liquids, try a full-liquid diet or a soft diet. Continue taking small amounts as often as you can keep them down. If you feel okay, gradually work up to your regular diet. If you have a hard time digesting milk, you may want to try a soft diet instead of a full-liquid diet, because a full-liquid diet includes a lot of milk products. Ask a registered dietitian for information about a soft diet.


Diarrhea may have several causes, including chemotherapy, radiation therapy to the abdomen, infection, food sensitivities, and emotional upset. Work with your doctor to identify the cause of your diarrhea so that it can be successfully treated.

During diarrhea, food passes quickly through the bowel before your body has a chance to absorb enough vitamins, minerals, and water. This may cause dehydration, which means that your body does not have enough water to work well. Long-term or severe diarrhea may cause problems, so contact your doctor if the diarrhea is severe or lasts for more than a couple of days. Here are some ideas for coping with diarrhea:

  • Drink plenty of fluids to replenish what you lose with the diarrhea.
  • Eat small amounts of food throughout the day instead of three large meals.
  • Eat plenty of foods and liquids that contain sodium and potassium, two important minerals that help your body work properly. These minerals are often lost during diarrhea. Good high-sodium liquids include bouillon or fat-free broth. Foods high in potassium that don’t cause diarrhea include bananas, peach and apricot nectar, and boiled or mashed potatoes. Sports drinks contain both sodium and potassium, and have easily absorbable forms of carbohydrates.
  • Avoid very hot or cold food or beverages. Drink liquids that are at room temperature.
  • Limit foods and drinks that contain caffeine, such as coffee, some sodas, and chocolate.
  • If you have a sudden, short-term attack of diarrhea, try having nothing but clear liquids for the next 12 to 14 hours. This lets your bowel rest and replaces the important fluids lost during the diarrhea. Make sure your doctor or nurse knows about this problem.
  • Be careful when using milk and milk products. The lactose they contain can make diarrhea worse. Most people, though, can handle small amounts (about 1-1/2 cups) of milk or milk products.

Try these foods:

  • Yogurt, cottage cheese
  • Rice, noodles, or potatoes
  • Farina or cream of wheat
  • Eggs (cooked until the whites are solid; not fried)
  • Smooth peanut butter
  • White bread
  • Canned, peeled fruits and well-cooked vegetables
  • Skinned chicken or turkey, lean beef, or fish (broiled or baked, not fried)


  • Greasy, fatty, or fried foods if they make your diarrhea worse
  • Raw vegetables and the skins, seeds, and stringy fibers of unpeeled fruits
  • High-fiber vegetables, such as broccoli, corn, dried beans, cabbage, peas, and cauliflower


Some anticancer drugs and other drugs, such as pain medications, may cause constipation. This problem also can occur if your diet lacks enough fluid or fiber, or if you’ve been in bed for a long time. Here are some suggestions for preventing and treating constipation:

  • Drink plenty of liquids—at least eight 8-ounce glasses every day. This will help to keep your stools soft. Another way to think about fluids is to try to drink at least 1/2 oz. per pound of your body weight.
  • Have a hot drink about one-half hour before your usual time for a bowel movement.
  • Check with your doctor to see if you can increase the fiber in your diet (there are certain types of cancer for which a high-fiber diet is not recommended). If you can, try foods such as whole-grain breads and cereals, dried fruits, wheat bran, wheat germ; fresh fruits and vegetables; dried beans and peas. Eat the skin on potatoes. Make sure you also drink plenty of fluids to help the fiber work.
  • Get some exercise every day. Talk to your doctors or a physical therapist about the amount and type of exercise that’s right for you.

If these suggestions don’t work, ask your doctor about medicine to ease constipation. Be sure to check with your doctor before taking any laxatives or stool softeners.

© Copyright FamilyCare America, Inc. All Rights Reserved.

Reprinted from Eating Hints For Cancer Patients Before, During, and After Treatment, NIH Publication #98-2079, developedby the United States National Institutes of Health National Cancer Institute.

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