What is chemotherapy?

Chemotherapy is a type of cancer treatment. Also called “chemo,” it’s one of several cancer treatments that use drugs against various types of cancer. Other drug therapies include:

  • Hormone therapy, or drugs that prevent certain cancers from getting the hormones they need to grow.
  • Immunotherapy, or drugs that help your immune system fight cancer.
  • Targeted therapy, or drugs that change how cancer cells multiply and behave.

A medical oncologist oversees treatment. These healthcare providers specialize in chemotherapy and other cancer-fighting drugs. Chemotherapy may get used with surgery or radiation therapy to treat cancer.

How does chemotherapy work?

Cancer cells grow and divide uncontrollably. Chemotherapy destroys the cancer cells and prevents them from multiplying.

Chemotherapy is used in different ways:

  • Adjuvant therapy: Chemotherapy destroys cancer cells after surgery or radiation therapy.
  • Curative therapy: Chemotherapy is the only treatment. It cures the cancer.
  • Neoadjuvant therapy: Chemotherapy shrinks a tumor before surgery or radiation therapy.
  • Palliative therapy: Chemotherapy shrinks tumors and lessens symptoms, but does not cure the cancer.

What types of cancer can chemotherapy treat?

Chemotherapy can treat a wide range of cancers, including:

  • Primary cancer, or cancer that has not spread to other areas of the body.
  • Metastatic cancer, or cancer that has spread to other areas of the body.

The type of chemotherapy you receive will depend on several factors:

  • Location of the cancer.
  • Stage of the cancer, or how advanced it is.
  • Your overall health.

Procedure Details

How is chemotherapy given?

Chemotherapy is usually systemic, meaning it travels throughout your entire body. Systemic chemo can get delivered:

  • As an injection, or a shot.
  • Intravenously, or through a vein as an “infusion.”
  • Orally, as a pill or liquid that you swallow.
  • Topically, as a cream that you rub into your skin.

Some cancers don’t respond well to systemic chemotherapy. In certain cases, you might need chemotherapy delivered to a specific area of your body. Examples include:

  • Intra-arterial chemotherapy, which goes into a single artery that supplies blood to a tumor.
  • Intracavitary chemotherapy, which goes directly into a body cavity, such as the bladder or belly. One form is hyperthermic intraperitoneal chemotherapy (HIPEC). It puts heated chemotherapy in the abdomen after surgery.
  • Intrathecal chemotherapy, which goes into the area between the brain and spinal cord.

How is intravenous chemotherapy given?

The most common way to give chemotherapy is intravenously. Chemotherapy can go directly into a vein through a:

  • Needle, usually in your arm.
  • Catheter, a thin, flexible tube attached to a vein (usually in your chest).
  • Port, a small disc inserted under the skin. A catheter attaches to the port to deliver chemotherapy. Port placement requires a minor surgery.

Catheters and ports are helpful if you need multiple rounds of chemotherapy. They avoid the need for constant needle sticks in your arm. Your healthcare provider may also use catheters and ports to deliver other medications. These may include antibiotics or antiemetics (medications to prevent nausea and vomiting).

The amount of chemotherapy you receive is usually controlled with a pump. The pump attaches to a catheter or port.

How long does a chemotherapy treatment take?

The length of a chemotherapy treatment depends on the type of chemo you receive. It can take anywhere from a few minutes to a few hours. Some people need a continuous infusion, which can last several days. A continuous infusion might get started at the hospital or infusion center and continued at home.

Most people need multiple rounds of chemotherapy. You may receive daily, weekly or monthly treatments.

Risks / Benefits

What are the side effects of chemotherapy?

Chemotherapy drugs destroy cancer cells, but they target all fast-growing cells, not just cancer cells. This means chemotherapy can damage other cells in your body, which may lead to side effects. Your skin, hair follicles and digestive tract are examples of cells that grow and multiply quickly. That’s why some common side effects of chemotherapy occur in these areas, including:

Talk to your care team about ways to manage the side effects of cancer treatment.

What are the benefits of chemotherapy?

Despite the potential side effects, chemotherapy has been an effective, reliable cancer treatment for decades. Chemo may cure cancer, or it can help you lead a better quality of life by reducing symptoms. Chemotherapy can also make other treatments, such as surgery or radiation therapy, more effective.

Recovery and Outlook

How long do the side effects of chemotherapy last?

Many side effects of chemotherapy will go away after you stop treatment. Some effects of chemotherapy, though, may not show up until months or years after treatment. Late effects of chemo can include:

Cognitive (memory and thinking) issues, also called “chemo brain.”

Many people find cancer rehabilitation helpful in managing the effects of cancer treatment.

Can cancer come back after chemotherapy?

Cancer can come back after chemotherapy or any type of cancer treatment. Once treatment ends, your care team often asks you to come for follow-up visits to check for disease. Your healthcare provider may recommend more cycles of chemotherapy to treat cancer that returns.

When to Call the Doctor

A note from Cleveland Clinic

Chemotherapy is one of the most common types of cancer treatment. Chemotherapy can work on its own or get paired with other treatments like radiation therapy or surgery. The type of chemotherapy you receive will depend on the location and stage of the cancer, as well as your overall health. Chemotherapy may cause side effects in the short term and long term. Before starting any cancer treatment, talk to your healthcare provider about the risks and benefits.

Last reviewed by a Cleveland Clinic medical professional on 05/14/2021.


  • American Cancer Society. How Is Chemotherapy Used to Treat Cancer? ( Accessed 5/7/2021.
  • American Cancer Society. Chemotherapy Side Effects. ( Accessed 5/7/2021.
  • American Society of Clinical Oncology. Catheters and Ports in Cancer Treatment. ( Accessed 5/7/2021.
  • American Society of Clinical Oncology. Long-Term Side Effects of Cancer Treatment. ( Accessed 5/7/2021.
  • National Cancer Institute. Chemotherapy. ( Accessed 5/7/2021.

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