What Is Chemotherapy?

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woman getting chemotherapy from healthcare provider
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Chemotherapy is a treatment that uses drugs to destroy cancer cells. Chemotherapy drugs can be given by mouth (orally), on the skin (topically), into a vein (intravenously), or through other routes. Healthcare providers recommend chemotherapy to treat or cure cancer in different areas of the body. However, this treatment usually affects cells in several areas of the body, and side effects are common.

An oncologist (a doctor who treats cancer) usually recommends a specific regimen of chemotherapy drugs based on your type of cancer and overall health. The treatment is usually administered by oncology nurses (nurses who specialize in cancer treatment).


The purpose of chemotherapy is to slow or stop the growth of cancer cells. Cancer cells tend to grow and divide quickly. Chemotherapy can also help shrink the size of a cancerous tumor, which can reduce painful symptoms. 

Depending on your type of cancer and how advanced it is, the three goals of chemotherapy are to:

  • Cure: When chemotherapy is successful at destroying all of the cancer cells in your body, it is considered a cure. Chemotherapy may also lower the risk of the cancer coming back.
  • Manage: If a cure is not possible, chemotherapy can be used to control the disease, shrink tumors, and prevent further spread. In these cases, cancer does not go away completely but can help you better manage your symptoms.
  • Comfort: In advanced stages of cancer, chemotherapy may be used to ease symptoms. At this point, the goal of chemotherapy is to improve your quality of life as much as possible.

Types of Chemotherapy 

There are several types of chemotherapy, each of which can fight cancer in different ways. Many people with cancer receive more than one type of chemotherapy during their treatment. The types are usually grouped by how they work and their chemical structure. Most types of chemotherapy drugs work by altering the DNA inside of cancer cells.

When developing your chemotherapy treatment plan, your oncologist will consider your type of cancer, how advanced it is, where it has spread, your age, and overall health. 

What Is DNA?

Deoxyribonucleic acid (DNA) is a molecule inside cells that carries your genetic information. DNA is needed for cells to function and multiply.

Alkylating Agents

Alkylating agents are chemotherapy drugs that work by keeping cancer cells from multiplying. These drugs damage the DNA of the cancer cells and prevent the cells from reproducing. This stops the spread of cancer throughout the body.

Most alkylating agents are used to treat leukemia, lymphoma, Hodgkin's disease, multiple myeloma, sarcoma, and cancers of the brain, lungs, breasts, and ovaries. However, they may damage the cells in the bone marrow and raise the risk of cancer over time.

Nitrosoureas are the only type of alkylating agent that can cross the blood-brain barrier and travel to the brain. They are used to treat brain cancer. Examples of alkylating agents include Temodar (temozolomide), Myleran (busulfan), and cyclophosphamide.


Antimetabolites are chemotherapy drugs that interfere with the DNA and RNA of cancer cells. This prevents the cells from reproducing and multiplying. 

Antimetabolites are used to treat leukemia and cancers of the gastrointestinal tract (the passageway between your mouth and anus that helps with digestion), breasts, and ovaries. Examples of antimetabolites include 5-FU (5-fluorouracil), 6-MP (6-mercaptopurine), Xeloda (capecitabine), and gemcitabine.

Anti-Tumor Antibiotics

Antitumor antibiotics treat cancer by changing the DNA inside of the cancer cells. By interfering with the enzymes (proteins) involved in copying DNA, they prevent cancer cells from reproducing.

Anti-tumor antibiotics are used to treat a variety of cancers. However, taking these drugs in high doses may cause long-term damage to the heart, so your healthcare provider will monitor you frequently while you take these medications. Examples of anti-tumor antibiotics include Cosmegen (dactinomycin), Blenoxane (bleomycin), Cerubidine (daunorubicin), and Adriamycin PFS (doxorubicin).

Topoisomerase Inhibitors

Topoisomerase inhibitors are plant alkaloids (drugs that come from plants) that interfere with the DNA of cancer cells. These drugs alter enzymes called topoisomerases which are needed to separate strands of DNA so that it can be copied. 

Topoisomerase inhibitors treat leukemia and cancers of the lungs, ovaries, and gastrointestinal tract. However, they may raise the risk of developing acute myeloid leukemia over time. Examples of topoisomerase inhibitors include etoposide, Camptosar (irinotecan), and Hycamtin (topotecan).

Mitotic Inhibitors

Like topoisomerase inhibitors, mitotic inhibitors are also plant alkaloids that work by stopping cancer cells from dividing into new cells. Your healthcare provider can recommend this type of therapy to treat myeloma, lymphoma, leukemia, and cancers of the breasts and lungs.

Common miotic inhibitors include Taxotere (docetaxel), Halaven (eribulin), Ixempra (ixabepilone), Taxol (paclitaxel), and vinblastine. Keep in mind: mitotic inhibitors may cause painful nerve damage.


Corticosteroids are medications that reduce inflammation (swelling) in the body. When used to treat cancer, they are considered chemotherapy drugs. Examples of commonly-used corticosteroids include prednisone, methylprednisolone, and dexamethasone.

How Is Chemotherapy Given?

There are many ways that you can receive chemotherapy drugs, including:

  • Oral: By mouth
  • Intravenous (IV): Into a vein
  • Injection: Into a muscle or fat tissue 
  • Intrathecal: Injected into the space between the layers of tissue that cover the brain and spinal cord
  • Intraperitoneal (IP): Injected into the peritoneal cavity (the space that contains the intestines, stomach, and liver)
  • Intra-arterial (IA): Into an artery or blood vessel
  • Topical: Onto the skin

How Does It Work?

Your healthcare provider can administer chemotherapy in regular intervals known as rounds or cycles. You will likely receive treatment regularly for days or weeks and then have a break. This break time allows your healthy cells to recover from chemotherapy and your body to get rest.

Chemotherapy may be given with other cancer treatments too. If you require surgery to remove a tumor, your care team may recommend chemotherapy before or after surgery to shrink the tumor or kill any remaining cancer cells. 

Before Chemotherapy

It takes some preparation to get ready for a chemotherapy appointment. If you are receiving chemotherapy in a hospital or outpatient clinic, your appointment could take several hours. 

Before your first chemotherapy appointment, you will meet with your oncologist to discuss your individualized care plan. Your healthcare provider will perform a physical exam, take blood tests, and ask about any medications or supplements you are taking. 

Ask your oncologist if there are any other medical procedures you should have before starting chemotherapy. For example, your care team will likely recommend a dental exam and teeth cleaning before cancer treatment starts. This is because the bacteria in the mouth can enter the bloodstream during dental procedures. Because chemotherapy weakens your body’s ability to fight infection, it’s best to have this done before chemotherapy starts. 

Your oncologist may also recommend meeting with a cardiologist (a doctor who specializes in the heart) because some forms of chemotherapy can cause long-term damage to your heart. Finally, chemotherapy can affect your fertility. If you hope to become a parent in the future, ask your oncologist about your options for preserving your fertility. 

During Chemotherapy

On the day of your chemotherapy appointment, consider asking a friend or family member to come with you. It might be nice to have some company during your long appointment. Make sure to ask your medical facility about any visitor restrictions first. 

Keep in mind: you may experience side effects after a chemotherapy session. One of the most common side effects of chemotherapy is fatigue. You may be too tired to drive yourself home after the appointment, so arrange for a ride. It may also be helpful to get help with household chores like cleaning and food preparation, as well as babysitting if needed. 

Before leaving for your appointment, eat a small, bland meal. Because the appointment is long, you’ll want some food in your stomach. However, chemotherapy often causes nausea so opt for bland foods like rice or toast. 

When you arrive at the hospital or clinic for your appointment, you will check in at the front desk. The healthcare team will check your vital signs including your heart rate, blood pressure, and temperature, as well as your height and weight.

Most people receive chemotherapy while sitting in a recliner-type chair. Your healthcare provider will likely place an IV in your arm to draw blood and give chemotherapy and fluids. They will then double-check your name, date of birth, medication, and dosage. If you need medications before chemotherapy, such as drugs to prevent an allergic reaction, you will receive them right away.

Once your chemotherapy starts, it may take several hours. During your appointment, the care team will monitor you for any signs of a drug reaction. They will also continue to check your vital signs throughout the appointment. 

To pass the time, consider bringing relaxing activities like books, podcasts, audiobooks, knitting, or crossword puzzles. Some people feel cold while receiving chemotherapy, so bring layers of clothing and a blanket as well. 

Ask your oncologist if it’s ok for you to eat during your appointment and bring a large water bottle and bland snacks. After your appointment, continue to stick with bland foods that don’t have a strong aroma. Cold or cool foods usually don’t have much of a smell. However, hot foods with strong aromas could trigger nausea. 

After Chemotherapy

After chemotherapy, there are some important precautions to keep in mind. If you received treatment in an outpatient facility, you will go home after your appointment. 

It takes your body about 48 to 72 hours to break down chemotherapy drugs. Any bodily fluids, such as urine and stool, will contain chemotherapy for the first few days after your appointment. If you live with others, it’s important to protect them from any chemotherapy exposure.

You can protect others from exposure in the following ways. If you have an extra bathroom, consider using your own away from your family. Always flush the toilet twice and close the lid, and remember to wash your hands throughout the day. If you have someone helping you during the day, ask them to wear two pairs of disposable gloves to protect themselves. 

In the days after chemotherapy, you will likely feel very tired. Engage in gentle exercise when you can but don’t feel the need to push yourself too hard. The important thing is to get your rest and do what you comfortably can while you are receiving treatment.

Risks and Precautions 

There are several risks and potential side effects associated with chemotherapy. Chemotherapy works by targeting cells that divide and multiply rapidly, which helps attack cancer cells living in your body. Unfortunately, there are healthy cells in the body that also divide quickly. These include cells in the skin, hair, mouth, and digestive tract. If chemotherapy attacks these cells, serious side effects occur. 

Common side effects of chemotherapy include:

Chemotherapy may also lead to long-term damage to the heart, kidneys, nerves, and reproductive system. 

When to Call Your Healthcare Provider

Because chemotherapy can lead to serious health problems, it’s important to monitor yourself for new symptoms and tell your oncologist right away. If you develop any of the following symptoms after receiving chemotherapy, call your provider right away:

  • Fever over 100.5 degrees Fahrenheit
  • Chills 
  • New bleeding or bruising 
  • Allergic reactions such as rash, swelling, itching, trouble swallowing or breathing
  • New-onset pain
  • Nausea and vomiting 
  • Blood in the stool or urine
  • Shortness of breath 

How to Prepare for Chemotherapy

Walking into your first chemotherapy appointment is an overwhelming experience. Being well-prepared may help to ease some of the anxiety you are feeling. It’s helpful to remember that there is no right or wrong way to feel as you begin cancer treatment. You will likely feel a wide range of emotions from hope for treatment success to worry about the future. 

Here are some tips to keep in mind when preparing for chemotherapy:

  • Location: Chemotherapy may be given in the hospital, at an outpatient facility, or at home. Ask your healthcare team where your appointments will take place. 
  • Attire: Plan to wear loose, comfortable clothing to your appointment. If you have a catheter or port placed, be sure that the healthcare provider can easily access it. Wearing a button-up shirt can be helpful for this. You may feel cold during your appointment, so bring layers of clothing, a hat, gloves, and a blanket. 
  • Food and drinks: Ask your oncologist about eating before and during your chemotherapy appointment. Prepare bland foods that don’t usually upset your stomach. Bring a large water bottle to your appointment.  
  • Medications: Chemotherapy may interact with several types of medications, vitamins, and supplements. Bring a list of all of your current medications to your appointments and ask your oncologist which ones to hold during chemotherapy intervals. 
  • Items to bring: When leaving for your chemotherapy appointment, bring any documents that your oncologist has given you, as well as your insurance card and identification card. These appointments tend to take several hours, so bring some quiet activities as well.  
  • Emotional support: Many outpatient facilities allow you to bring a friend or family member with you. Because of visitor restrictions during COVID-19, it’s important to call ahead and ask about their visitor policy before your appointment. 
  • Cost and insurance: The cost of chemotherapy will depend on the exact drugs used and your insurance coverage. Call your insurance company and hospital billing department before your first appointment to determine if you will need to pay a copay when you check in for your appointment.  
  • Returning to work: Chemotherapy affects everyone differently, and you may experience significant side effects during the treatment process. Talk with your employer about a modified work schedule if possible. Many employers in the United States are required by law to change your work schedule to meet your health needs.

A Quick Review 

Chemotherapy is a cancer treatment that uses drugs to slow and stop the growth of cancer cells. It is a common cancer treatment and is sometimes used in combination with other treatments like radiation therapy, surgery, immunotherapy, or targeted therapy. 

Chemotherapy is usually prescribed by an oncologist—a doctor who specializes in the diagnosis and treatment of cancer. During your chemotherapy appointments, you can expect oncology nurses to administer the treatment. Chemotherapy may be given in the hospital, at an outpatient facility, or at home. 

There are several different types of chemotherapy, and your oncologist will consider your type of cancer, how advanced it is, and your overall health when recommending chemotherapy. Before beginning treatment, talk to your provider about any concerns or questions you have. Living with cancer can be difficult and scary. Get all the information and support you need to make this journey as comfortable as possible for you.

Frequently Asked Questions

  • At what stage of cancer does a healthcare provider recommend chemotherapy?

    Your oncologist will recommend a treatment plan based on your type of cancer, how advanced it is, and your overall health. Chemotherapy is a common cancer treatment and can be used at any stage of the disease. In the early stages, chemotherapy can be used to cure or manage the disease. In later stages, chemotherapy may be used to ease symptoms and provide pain relief. 

  • How fast does hair fall out with chemo?

    The side effects you experience from chemotherapy will vary depending on which types of drugs are used and their dosages. If you experience hair loss, it usually occurs within the first month. 

  • How long do you stay sick after chemo?

    It is possible to feel very fatigued and nauseous after chemotherapy. Most people feel sick for the first week after their chemotherapy appointment. Your symptoms will vary depending on which chemotherapy drugs you received and how high the dose was.

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9 Sources
Health.com uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Cancer Institute. Chemotherapy.

  2. MedlinePlus. Cancer chemotherapy.

  3. American Cancer Society. What is chemotherapy?.

  4. American Cancer Society. Goals of chemotherapy.

  5. MedlinePlus. Types of chemotherapy.

  6. American Cancer Society. How does chemo work?.

  7. American Cancer Society. Chemotherapy safety.

  8. Schirrmacher V. From chemotherapy to biological therapy: A review of novel concepts to reduce the side effects of systemic cancer treatment (Review). Int J Oncol. 2019;54(2):407-419. doi:10.3892/ijo.2018.4661

  9. American Cancer Society. Chemotherapy side effects.

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