Chemotherapy is medication(s) used to kill cancer cells. The medications are toxic to fast-growing cells like cancer cells.

Side Effects

Chemotherapy drugs attack fast-growing cells. Chemotherapy can damage these healthy cells which leads to side effects. The exact types of side effects will vary. They will depend on the type of chemotherapy treatment and which healthy cells are affected.

Cells that line the mouth, stomach, and intestines are fast-growing cells. Chemotherapy can damage these cells and cause:

  • Nausea or vomiting
  • Diarrhea or constipation
  • Appetite loss
  • Mouth sores

Damage to blood cells can lead to:

  • Anemia—low red blood cell count
  • Weakened immune system with an increased risk of infections
  • Fatigue
  • Easy bruising and/or bleeding

Cells at the root of hairs are also fast growing. Damage to these cells causes hair loss.

Other areas that may be affected include:

  • Nerves—damage or irritation to the nerves may cause peripheral neuropathy, numbness and tingling sensation in the hands and/or feet
  • Kidney—chemotherapy drugs eventually pass through the kidneys can damage to the kidneys
  • Heart—certain chemotherapy drugs can cause damage to the heart muscle
  • Reproductive organ changes may cause:
    • Infertility
    • Interruption of the menstrual cycle

The medical team will work to find a chemotherapy plan that is most effective against the cancer with the fewest amount of side effects. Other treatments may also help better manage side effects.



This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

Edits to original content made by Denver Health.


American Cancer Society 

National Cancer Institute 


BC Cancer Agency 

Canadian Cancer Society 


Chemotherapy. American Cancer Society website. Available at: Accessed October 9, 2017.

Chemotherapy and you: Support for people with cancer. National Cancer Institute website. Available at: Updated June 2011. Accessed October 9, 2017.