What to Expect With Chemotherapy

Chemotherapy ("chemo") is a type of cancer treatment that uses drugs that kill fast-replicating cells like cancer cells. Chemotherapy can be used to cure cancer, to clear any remaining cancer cells after surgery, or to prolong life in those who cannot undergo surgery or have advanced cancer.

Chemotherapy drugs cause side effects because they not only kill fast-replicating cancer cells but other fast-replicating cells as well, such as those in the mouth, intestines, and hair. This accounts for common side effects like mouth sores, nausea, and hair loss. To minimize side effects and ensure the best results, chemo is administered in cycles with periods of recovery in between.

This article explains how chemotherapy works, including its uses, drug types, methods of administration, and side effects. It also offers tips on how to cope and speak with your cancer specialist about chemotherapy.

Patients and doctor in infusion room
Isaac Lane Koval/Corbis/VCG / Getty Images

How Chemotherapy Works

A cell becomes cancerous when an accumulation of mutations causes it to reproduce and divide out of control.

Local treatments, such as surgery and radiation therapy, treat cancer where it begins. In contrast, chemotherapy is a systemic (whole-body) treatment that uses drugs to "search and destroy" cancer cells wherever they are in the body.

Chemotherapy drugs are cytotoxic, meaning toxic to cells. They work by interfering with the cell division of any rapidly growing cells in the body.

Chemotherapy can not only treat the primary (original) tumor but also areas where cancer has spread (metastasized). These include micrometastases that may not be spotted in imaging studies.

Chemotherapy is also invaluable in the treatment of blood cancers like leukemia that freely circulate in the bloodstream.

Cancer cells that grow rapidly respond well to chemotherapy. In contrast, slow-growing cancers, like certain types of lymphoma, respond less well or not at all.

Ways That Chemotherapy Is Used

Chemotherapy may be given for different reasons and with several different goals in mind. It's important to talk to your healthcare provider and understand the exact purpose of chemotherapy as part of your treatment plan.

The purpose of chemotherapy may be:

  • Curative therapy: With early-stage cancers and blood cancers, chemotherapy is often given with the intent of curing the cancer, also known as "remission."
  • Adjuvant chemotherapy: This is chemo given after the primary tumor is killed to clear any cancer cells that may be remaining.
  • Neoadjuvant chemotherapy: This is chemo given before surgery to shrink the tumor so that is more easily removed.
  • Maintenance chemotherapy: This is sometimes used to maintain remission or to that cannot be fully removed from growing.
  • Palliative chemotherapy: This is used for people who cannot be cured to reduce any pain or suffering caused by the cancer.

Type of Chemotherapy Drugs

There are several types of chemotherapy drugs, which vary both in how they work (mechanisms) and where they work (what part of the cell cycle). Some drugs work on one of the four primary phases of cell division, whereas others—termed phase non-specific drugs—may work at multiple points.

Some of these classes of drugs include:

  • Alkylating agents: This is the most commonly used class of drug used to treat a wide variety of cancers. Examples include Cytoxan (cyclophosphamide) and Myleran (busulfan).
  • Antimetabolites: These drugs work by pretending to be a nutrition source. Cancer cells take them up instead of nutrients and essentially starve to death. Examples include Navelbine (vinorelbine), VP-16 (etoposide), and Gemzar (gemcitabine).
  • Plant alkaloids: This class includes drugs obtained from plant sources. Examples include Cosmegen (dactinomycin) and Mutamycin (mitomycin).
  • Antitumor antibiotics: These drugs work by preventing cancer cells from reproducing. Examples include Adriamycin (doxorubicin), Cerubidine (daunorubicin), and Bleo 15K (bleomycin).

Combination Chemotherapy

A combination of different chemotherapy drugs, rather than a single drug alone, is usually used to treat cancer. There are several reasons for combination chemotherapy.

Cancer cells in a tumor are not all in the same place in the process of growth. Using drugs that affect the cell cycle at different points in multiplication and cell division increases the chance that as many cancer cells as possible will be treated.

Using a combination of medications may also allow healthcare providers to use lower doses of several agents, rather than a higher dose of a single agent, thereby decreasing the toxicity of the therapy (and related side effects).

Combination Chemotherapy Acronyms

Acronyms are often used to describe chemotherapy protocols. For example, BEACOPP is a seven-drug regimen used in the treatment of Hodgkin's lymphoma.

How Chemotherapy Is Given

Chemotherapy may be given in several different ways depending on the particular drug. Methods include:

  • Intravenous injection (IV): Many chemotherapy drugs are given intravenously (into a vein) using a peripheral line that is inserted in a vein with every infusion or a central venous catheter implanted under the skin with a chemotherapy port.
  • Intramuscular injection (IM): These are delivered by injection into a large muscle.
  • Subcutaneous injection (SubQ): These are delivered by injection just beneath the skin
  • Intrathecal chemotherapy: These are given by injection into the fluid-filled space between the membranes that cover the brain and spinal cord.
  • Intraperitoneal chemotherapy: These are directly into the abdominal cavity (peritoneal space).
  • Oral therapy: These are given by mouth as a pill, capsule, or liquid.

How Long Does Chemotherapy Last?

Chemotherapy is usually given over the course of sessions, called a cycle, and separated by a period of around two to four weeks where your body is allowed to recover. Chemotherapy is typically given in a specialized infusion center.

Since chemotherapy treats cells that are in the process of cell division—and cancer cells are all in different states of division—repeated cycles allow a greater chance to treat as many cancer cells as possible.

The amount of time between sessions will vary depending on the drugs being used, but it is often scheduled at a time when your blood count is expected to return to normal.

Side Effects of Chemotherapy

Some normal cells in your body divide rapidly just like cancer cells, they can also be affected by chemotherapy. Examples include cells of the digestive tract, hair follicles, and bone marrow, which accounts for the well-known chemo side effects of nausea, hair loss, and nausea.

Keep in mind that everyone responds to chemotherapy differently. Some people may have several of these side effects, while others may have none.


Fatigue is the most common side effect of chemotherapy, affecting nearly everyone who receives these treatments. Unfortunately, this kind of fatigue isn't the type of tiredness that responds to a cup of coffee or a good night's sleep.

There are a number of things that may help you cope with cancer fatigue, but the most important one is to allow yourself the extra time you need for rest.

Nausea and Vomiting

Nausea and vomiting are among the most feared side effects of chemo, but prevention and treatment of these symptoms have improved dramatically in recent years. Anti-nausea drugs (antiemetics) are frequently given along with chemotherapy drugs to prevent nausea.

Adjustment in diet can also help ease chemotherapy-induced nausea and vomiting.

Hair Loss

Hair loss is common with chemotherapy, and though it's not dangerous to your physical health, it can be very distressing emotionally. Hair loss commonly begins two to three weeks after your first treatment with regrowth occurring rapidly after your final treatment.

Not all chemotherapy drugs cause hair loss, and some people on the same drug may experience hair loss while others won't. Some people deal with hair loss by preemptively shaving their heads or wearing a scarf or wig. Others may be able to prevent it with scalp-cooling devices that may reduce hair follicle loss.

Bone Marrow Suppression

Suppression of the bone marrow is one of the more dangerous side effects of chemotherapy, but management of it—especially the risk of infections due to a low white blood cell count—has improved substantially in recent years.

All of your blood cells (white blood cells, red blood cells, and platelets) are formed from stem cells in the bone marrow. Since these are very rapidly dividing cells, all of them can be reduced by chemotherapy. Your oncologist will check a complete blood count (CBC) prior to each chemotherapy infusion and monitor your levels closely.

Mouth Sores

Around 30% to 40% of people will experience chemotherapy-induced mouth sores during treatment, though some medications are more likely than others to cause this symptom. If you are receiving drugs likely to cause mouth sores, your chemotherapy nurse may encourage you to suck on an ice pop or ice chips while the drug is infused.

A few dietary adjustments can help ease symptoms. This includes avoiding citrus fruits, spicy or salty foods, extremely hot or cold foods, or foods with sharp edges (like crackers).

There is also a product called "magic mouthwash" used to treat chemo-related mouth sores.

Peripheral Neuropathy

Burning, tingling, or prickly sensations in the hands and feet are symptoms of chemotherapy-induced peripheral neuropathy. This affects roughly a third of people receiving chemotherapy.

Some drugs, most notably so-called platinum agents, are more likely to cause this. They do so by damaging the outer coating of nerve cells, called myelin, and disrupting the normal processing of nerve signals.

Unlike many of the symptoms associated with chemotherapy, neuropathy often persists well after chemotherapy is completed.

Bowel Changes

Chemotherapy drugs can cause bowel changes ranging from constipation to diarrhea, depending on the drug. Constipation is also common with drugs used to prevent nausea, and your healthcare provider may recommend stool softeners or laxatives if symptoms are severe.

Diarrhea can quickly become a problem as it contributes to dehydration. Certain foods can help, but make sure to talk to your practitioner promptly if you have this issue.

Sun Sensitivity

Many chemotherapy drugs increase your chance of getting a sunburn when you go out in the sun, something referred to as chemotherapy-induced phototoxicity. Sunscreen alone may not be effective and may irritate your skin, especially if you are also receiving radiation therapy. The best way to deal with this is to stay out of the sun.

"Chemo Brain"

The term "chemo brain" has been coined to describe the cognitive effects some people experience during chemotherapy. Symptoms range from forgetfulness to difficulty concentrating. Some people find that keeping their minds active with word puzzles, sudoku, and other "brain teasers" can help them focus while on chemo.

Possible Risks and Complications

With all cancer treatments, the benefits of treatment need to be weighed against the possible risks. While eradicating or managing your cancer is your primary concern, it's important to be aware of how chemotherapy might affect you months or even years after the completion of cancer treatment.

As with the short-term side effects, the odds that you will experience these issues depend on the particular chemotherapy drugs you receive.

Heart Disease

Some chemotherapy drugs, especially drugs such as Adriamycin (doxorubicin), can cause heart damage. The type of damage may range from heart failure to valve problems to coronary artery disease.

If you are receiving any of these drugs, your healthcare provider may recommend a heart test before you begin treatment. Radiation therapy to the chest may also increase the risk of heart-related problems.


Many chemotherapy drugs result in infertility after treatment. If there is a chance you would like to conceive after chemotherapy, options such as freezing sperm or freezing embryos have been used successfully by many people. Make sure to have this discussion before starting treatment.

Secondary Cancers

Since some chemotherapy drugs work by causing DNA damage in cells, they may not only treat cancer but predispose someone to developing secondary cancer as well.

An example of this is the development of leukemia in people who have been treated with Cytoxan (cyclophosphamide), a drug commonly used in breast cancer treatment. These cancers often occur five to 10 years or more after chemotherapy has been completed.

Other Risks

Other possible late effects may include symptoms ranging from hearing loss or cataracts to lung fibrosis. Though the benefits of treatment often outweigh the risks, take a moment to talk with your healthcare provider about side effects that may be unique to your particular chemotherapy regimen.

Questions to Ask Your Healthcare Provider

A cancer diagnosis thrusts you into a world of details—a lot of which are not always easy to understand. As you work to get a better hold on what chemotherapy may mean for you before, during, and after your course, you may find it helpful to ask your healthcare provider these questions:

  • What specific chemotherapy drugs are being recommended?
  • Are there alternatives to these drugs?
  • How will the drugs be given?
  • How often will I have infusions? How many cycles will be needed?
  • Where will chemotherapy treatments take place?
  • How and when will you know if chemotherapy is working?
  • What is your "plan B" if chemotherapy isn't working?
  • What are the more common side effects?
  • How can I manage side effects?
  • Do I need birth control while on chemo?
  • How much will the treatment cost?
  • Who should I call if I have any problems day or night?

Coping With Chemotherapy

Most people lead busy lives before a diagnosis of cancer. Facing chemotherapy may have you wondering if you can manage your normal commitments and obligations along with chemo. Take a moment to consider what support you will need to keep your life running smoothly.

Reach out to friends for help with errands and childcare or to simply share your feelings. To build a support team, launch a personal site Caring Bridge to share updates on how your treatment is going. These sites can also be a tremendous source of encouragement and allow friends to send love without worrying about disturbing you.

Sites such as Lotsa Helping Hands can be invaluable in organizing tasks among those who have volunteered to help, whether it be preparing a meal or helping with housework.


Chemotherapy is a form of cancer treatment that uses different systemic drugs that kill fast-replicating cells like cancer. The treatment is delivered in cycles, most often by intravenous infusion but also by mouth or injection.

Because chemo also kills fast-replicating cells of the digestive tract, hair, mucus membranes, and other tissues, you might experience side effects like nausea, hair loss, mouth sores, peripheral neuropathy, and "chemo brain." It is important to remember that some people have few side effects and that the experience differs greatly from one person to the next.

Support from your care team and loved ones can help you prepare for and cope with chemotherapy.

7 Sources
Verywell Health 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.
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Additional Reading
  • American Society of Clinical Oncology. Cancer.Net. Understanding Chemotherapy.

  • Longo, D. L. Harrison's Principles of Internal Medicine. 2017. New York: McGraw-Hill.

  • National Cancer Institute. SEER Training Manual. Types of Chemotherapy Drugs.

  • Niederhuber, J., Armitage, J., Doroshow, J., Kastan, M., and J. Tepper. Abeloff's Clinical Oncology: 6th Edition. 2019. Philadelphia: Churchill Livingstone/Elsevier.

By Lynne Eldridge, MD
 Lynne Eldrige, MD, is a lung cancer physician, patient advocate, and award-winning author of "Avoiding Cancer One Day at a Time."