Side Effects of Chemotherapy

Approved by the Cancer.Net Editorial Board, 11/2016

Chemotherapy treats many types of cancer effectively. However, like other treatments, it often causes side effects. Specific side effects depend on these factors:

  • Cancer type

  • Cancer location

  • Drugs and doses

  • Your general health

Why chemotherapy causes side effects

Chemotherapy works on active cells. Active cells grow and divide. Cancer cells are active. And some healthy cells are active. These include cells in your blood, mouth, digestive system, and hair follicles. Side effects happen when chemotherapy damages healthy cells.

Managing side effects

Your health care team can help you prevent or treat many side effects. Preventing and treating side effects is an important part of cancer treatment. This approach is called supportive or palliative care.

Also, doctors and scientists work constantly to develop drugs, drug combinations, and ways of giving treatment with fewer side effects. Many types of chemotherapy are easier to tolerate than they were a few years ago.

Common side effects

Different drugs cause different side effects. Certain types of chemotherapy have common side effects. But each person’s experience is different.

Tell your doctor about all side effects that you notice. Typically, having side effects doesn’t mean the treatment isn’t working. But certain side effects of drugs called targeted therapies may cause concern. Learn more about targeted therapy.

Below is a list of common side effects of traditional chemotherapy:

Fatigue. This is a persistent feeling of physical, emotional, or mental exhaustion. Cancer-related fatigue differs from feeling tired due to lack of rest. Receiving multiple treatment types may increase your fatigue. For example, having chemotherapy and radiation therapy. Learn more about how to cope with fatigue.

Pain. Chemotherapy sometimes causes these types of pain:

  • Headaches

  • Muscle pain

  • Stomach pain

  • Pain from nerve damage. For example, burning, numbness, or shooting pains, usually in the fingers and toes. This is called peripheral neuropathy.

Ways doctors treat pain:

  • Treating the source of the pain

  • Giving pain-relieving medications

  • Blocking pain signals from the nerves to the brain with spinal treatments or nerve blocks

Learn more about cancer-related pain.

Mouth and throat sores. Chemotherapy can damage mouth and throat cells. This causes painful sores, a condition called mucositis. It usually happens 5 to 14 days after a treatment. Mouth sores usually go away completely when treatment ends.

To prevent infection of mouth sores, eat a healthy diet. Also keep your mouth and teeth clean. Learn more about managing mucositis and oral health during cancer treatment.

Diarrhea. This means having loose or watery bowel movements. Prevention and early treatment helps limit dehydration, which is the loss of too much body fluid. It also helps prevent other health problems. Learn more about managing diarrhea.

Nausea and vomiting. These side effects may appear, depending on the specific drug and dose. Typically, medications given before and after each dose of chemotherapy limit nausea and vomiting. Learn more about nausea and vomiting and read ASCO’s guideline for preventing these side effects.

Constipation. This means having infrequent or difficult bowel movements. Other medications, such as pain medication, also cause constipation. To lower your risk, drink enough fluids, eat balanced meals, and exercise. Learn more about managing constipation.

Blood disorders. Bone marrow is the spongy tissue inside your bones. It makes new blood cells. But chemotherapy affects this process. Therefore, you may experience side effects from having too few blood cells.

Your health care team uses the following tests to check for blood disorders:

  • A complete blood count (CBC) shows your levels of red blood cells (RBCs) and white blood cells (WBCs). Having too few RBCs causes a condition called anemia. Symptoms include fatigue, dizziness, and shortness of breath. Meanwhile, having too few WBCs causes a condition called leukopenia. This raises your risk of getting infections.

  • A platelet count measures the number of platelets in your blood. Platelets are cells that stop bleeding. They plug damaged blood vessels and help blood form clots. Having too few platelets causes a condition called thrombocytopenia. It means you may bleed and bruise more easily than normal.

Doctors may prescribe medications to treat these blood disorders and prevent leukopenia. The medications help your bone marrow make more blood cells. Learn more about managing anemia, infection, and thrombocytopenia.

Nervous system effects. Some drugs cause nerve damage. Nerve or muscle symptoms may include the following:

  • Tingling

  • Burning

  • Weakness or numbness in the hands, feet, or both

  • Weak, sore, tired, or achy muscles

  • Loss of balance

  • Shaking or trembling

  • Stiff neck

  • Headache

  • Problems seeing, hearing, or walking normally

These symptoms usually get better by lowering the chemotherapy dose or after treatment ends. However, sometimes, damage is permanent. Learn more about managing nervous system side effects.

Changes in thinking and memory. Some people have trouble thinking clearly and concentrating after chemotherapy. Cancer survivors often call this chemo brain. Your doctor might call it cognitive changes or cognitive dysfunction.

Sexual and reproductive issues. Chemotherapy can affect your fertility. For women, this is the ability to get pregnant and carry a pregnancy. For men, fertility is the ability to father a child. In addition, fatigue and other side effects can affect your ability to enjoy sex. Talk with your doctor about these possibilities before treatment starts. Learn more about managing sexual and reproductive side effects.

Chemotherapy can harm an unborn baby. Particularly within the first 3 months of pregnancy. During that time, organs are still developing. If you could become pregnant, use effective birth control. If you become pregnant, tell your doctor right away. Learn more about pregnancy and cancer.

Appetite loss. This symptom may take various forms. You may:

  • Eat less than usual

  • Experience a lack of hunger

  • Feel full after eating a small amount

If this lasts through treatment, the following may occur:

  • Weight loss

  • Malnutrition, which means not getting the nutrients your body needs

  • Loss of muscle mass and strength

These symptoms may make it harder to recover from chemotherapy. Learn more about managing appetite loss.

Hair loss. Some types of chemotherapy cause hair loss. It may come out gradually or in large clumps. Hair loss usually starts after several weeks of chemotherapy. It tends to increase 1 to 2 months into treatment. Your doctor can predict the risk of hair loss based on the drugs and doses you will receive. Learn more about managing hair loss.

Radiation recall. Radiation recall is a rash that looks like a severe sunburn. Although rare, it occurs when certain types of chemotherapy are given during or soon after external beam radiation therapy.

The rash appears on the part of the body that received radiation therapy. Symptoms may include redness, tenderness, swelling, wet sores, and peeling skin.

Typically, radiation recall appears days or weeks after you receive radiation therapy. It can also appear months or years later. Doctors treat radiation recall with medications called corticosteroids. Rarely, you may wait until the skin heals before continuing chemotherapy.

Long-term side effects. Most side effects go away after treatment. But some continue, come back, or develop later. Some types of chemotherapy may permanently damage the heart, lungs, liver, kidneys, and/or the reproductive system. Sometimes, cognitive changes may last for months or years after treatment.

Nervous system changes can also develop after treatment. Children who had chemotherapy may develop side effects months or years after treatment. These are called late effects. Cancer survivors also have a higher risk of second cancers later in life.

Follow-up care after cancer treatment

Your health care team can help you treat long-term side effects and watch for late effects. This is called follow-up care. Your follow-up care might include regular physical examinations, medical tests, or both.

ASCO has cancer treatment summary forms. These forms help you track the cancer treatment you receive and develop a survivorship plan after treatment.

More Information

Side Effects

Fear of Treatment-Related Side Effects

Additional Resources

National Cancer Institute: Chemotherapy and You

CancerCare: Understanding and Managing Chemotherapy Side Effects