An Overview of What Happens During Chemotherapy

When you are starting chemotherapy, your healthcare provider will explain the drug being used, the length of your treatment, and which side effects may occur. This treatment is usually given in regular cycles. Throughout these cycles, you will receive either one chemotherapy drug or a combination with other chemotherapies or treatment types.

Here’s what you need to know about what happens during chemotherapy.

Oncology patient

FatCamera / Getty Images

What Is Chemotherapy?

Chemotherapy is a cancer treatment that uses chemicals to attack and kill cancer cells.

Chemotherapy is considered a systemic treatment because the medication travels throughout your body. This is different from surgery that affects one specific area of the body.

Because chemotherapy affects the entire body, it is able to treat the primary cancerous tumor, as well as any metastases throughout the body.

How Does It Work?

Chemotherapy fights cancer by targeting and killing fast-growing cells in the body. This is because cancer cells grow and divide quickly. Unfortunately, that means that chemotherapy also targets healthy cells in the body. When healthy cells are destroyed, side effects occur. 

Chemotherapy fights cancer by interrupting the cell cycle. Any time a new cell is formed, it goes through the process of becoming a mature cell. During this period of maturing, chemotherapy targets cells at different points in the cell cycle. 

Normal cells that are targeted by chemotherapy are typically located in the:

  • Bone marrow
  • Hair follicles
  • Mouth
  • Digestive tract
  • Reproductive system

Chemotherapy is also capable of damaging cells in the heart, kidneys, bladder, lungs, and nervous system. The goal with chemotherapy treatment is always to find the minimum dose to effectively kill cancer cells while sparing as many healthy cells as possible. Fortunately, normal cells can recover from the effects of chemotherapy. Cancer cells, on the other hand, cannot. 

Chemotherapy works by targeting and killing fast-growing cells in the body. It does this by interrupting the cell cycle.

Types of Chemotherapy

There are several different forms of chemotherapy, including:

  • Alkylating agents: These drugs keep cells from reproducing by damaging their DNA.
  • Nitrosoureas: This group of alkylating agents is able to cross the blood-brain barrier and treat brain tumors. 
  • Antimetabolites: These drugs prevent cells from reproducing by acting as a substitute for the normal building blocks of RNA and DNA.
  • Antibiotics: Unlike antibiotics used to treat infections, these drugs prevent cancer cells from growing and multiplying by changing the DNA inside of them.
  • Topoisomerase inhibitors: Also known as plant alkaloids, these drugs prevent cancer cells from reproducing by interfering with enzymes used to help separate strands of DNA.
  • Mitotic inhibitors: These plant alkaloids are able to damage cells in all phases of the cell cycle by keeping enzymes from making needed proteins.
  • Corticosteroids: When steroids are used in combination with chemotherapy drugs, they are considered chemotherapy drugs themselves. 

Other types of cancer treatments include:

  • Targeted therapies: These drugs are similar to chemotherapy because they kill cells during the cell cycle. The advantage of targeted therapies is that they are able to target cancer cells and spare healthy cells.
  • Hormone therapy: Hormones affect certain types of cancers and cause cancer cells to grow and reproduce. Hormone therapy targets the cancer cells and keeps them from being able to use the hormones that naturally occur in the body. 
  • Immunotherapy: This treatment works to boost the immune system’s response to cancer cells so that it can better target and destroy them. 

How Chemo Cures Cancer

There are three goals of chemotherapy: cure, control, and provide palliative care.

The first goal of chemotherapy is always to cure cancer. This is possible when chemotherapy effectively kills all of the cancer cells in the body and prevents them from coming back. However, a cure is not always possible. 

How It Controls Cancer

The next goal of chemotherapy is to control cancer. Chemo may be used to shrink tumors or stop cancer cells from spreading in order to provide a longer and better quality of life. Once cancer cells have been controlled, then cancer can be managed and treated like a chronic health condition, similar to heart disease. 

Finally, the last goal of chemotherapy is to provide palliative care. In cases of advanced cancer, chemo may be used to provide better pain control and comfort. This is possible when chemotherapy shrinks a large tumor to relieve pain or shortness of breath. 

What Happens During Chemotherapy?

During a chemotherapy appointment, your healthcare provider will explain the drug being used, how long treatment will last, and which side effects may occur.

Chemotherapy drugs can also cause harm to anyone who handles them or comes in contact with them. The health provider who administers your treatment will likely wear protective clothing and goggles or a face shield. 

Your treatment plan may include one chemotherapy drug, but more likely, the plan will include a combination of medications. This is referred to as combination chemotherapy.

Chemotherapy may also be combined with other treatment types like surgery, radiation, immunotherapy, hormone therapy, and targeted therapies. 

How Do I Know What Type I Need?

The type of chemotherapy chosen for your treatment will depend on a variety of factors, including your type of cancer, how advanced it is, your age and overall health, and the other types of cancer treatment you are receiving.

Chemotherapy is usually given in regular intervals known as cycles. A cycle often includes a day of treatment followed by several days to recover. This gives your body a chance to rest and recover from any side effects. 

If the dose or type of drug that you are receiving causes significant side effects, your doctor will work with you to adjust your treatment plan. This may include trying a new drug. 

During a chemotherapy appointment, you will receive chemotherapy from a healthcare provider. It is also possible to take oral chemotherapy at home.

The Ways Patients Can Receive Chemo

Methods of chemotherapy administration include: 

  • IV push: The medication is given through an intravenous catheter with a syringe over a few minutes.
  • IV infusion: The medication is given intravenously through tubing and is usually controlled by an IV pump.
  • Continuous infusion: The medication is given intravenously over one to several days. 
  • Oral: The medication is given in the form of a pill or capsule and swallowed by mouth. 
  • Topical: The medication is placed directly on the skin in the form of a cream or ointment. 
  • Intrathecal: The medication is delivered to the fluid that surrounds the spinal cord (cerebrospinal fluid) via a catheter. 
  • Intra-arterial: The medication is put into a major artery that supplies blood to the tumor.
  • Intracavity: The medication is given through a catheter to a body cavity such as the bladder or abdomen. 
  • Intramuscular: The medication is injected into a muscle with a syringe. 
  • Intralesional: The medication is placed directly into the tumor through a needle.
  • Intravesical: The medication is placed into the bladder through a soft catheter. 

Depending on the type of chemo given, you may receive your treatment in an outpatient clinic, hospital, doctor’s office, infusion center, or your home. 

How Long Does the Treatment Last?

Your treatment schedule will depend on your type of cancer, how advanced it is, and how well your body is responding to treatment. Chemotherapy treatments may be given daily, weekly, or monthly. Most treatments require recovery time afterward. 

Ask your medical team how to best prepare for your first chemotherapy appointment. It could take several hours, so make a plan to eat a light meal or snack before you go. Ask your doctor if there is any reason that you should avoid food before treatment. 

Long- and Short-Term Symptoms of Chemotherapy

It’s helpful to remember that while there is a long list of possible side effects, you may experience very few. Each person is different, and your chemotherapy regimen will be unique to you. 

Let your doctor know as soon as you develop any new side effects. There are medications available to relieve some of the symptoms caused by chemotherapy. 

Many chemotherapy side effects resolve quickly. However, some are long term and may last for months or even years. Occasionally, the side effects from chemotherapy are permanent. Possible permanent complications include heart damage, lung damage, kidney damage, and infertility.

According to the American Cancer Society, the most common side effects of chemotherapy are:

  • Fatigue
  • Hair loss
  • Easy bruising and bleeding
  • Infection
  • Anemia (low red blood cell counts)
  • Nausea and vomiting
  • Appetite changes
  • Constipation
  • Diarrhea
  • Mouth, tongue, and throat problems, such as sores and pain with swallowing
  • Peripheral neuropathy or other nerve problems, such as numbness, tingling, and pain
  • Skin and nail changes, such as dry skin and color change
  • Urine and bladder changes and kidney problems
  • Weight changes
  • Chemo brain, which can affect concentration and focus
  • Mood changes
  • Changes in libido and sexual function
  • Fertility problems

What to Expect After Chemotherapy

You may experience side effects after receiving chemotherapy. It’s important to stay in close contact with your medical team during and after chemotherapy treatment cycles.

If you experience any of the following symptoms, call your doctor right away:

  • Fever
  • Intense chills
  • Bleeding
  • Rash
  • Pain 
  • Shortness of breath 
  • Blood in the stool, urine, or vomit
  • Uncontrolled vomiting or diarrhea 
  • Headache 
  • Allergic reaction 

Safety Precautions

Any time you receive chemotherapy, it will be excreted in your urine and stool. This means that you and anyone else who comes in contact with your bodily fluids must take precautions. 

It takes about 48 to 72 hours for your body to break down chemotherapy after treatment. During this time, it’s important to take extra precautions to protect yourself and anyone else in your household.

Because chemotherapy will be present in your bodily fluids, it’s best to use a separate bathroom from the rest of your family. This is not always possible. 

After using the restroom, flush the toilet twice and then keep the lid closed when not in use. If you vomit into the toilet, flush twice and wipe away any splashes. Wash your hands after using the bathroom or coming in contact with any of your bodily fluids. 

If you have a home health nurse or a family member caring for you, they should wear two pairs of gloves any time they handle your bodily fluids, and then thoroughly wash their hands with warm water.

Any clothing items or bed linens with bodily fluids on them must be washed right away. If that is not possible, keep them sealed in two plastic bags.

After chemotherapy, you may experience short-term side effects, long-term side effects, or both. For the first 48 to 72 hours after treatment, take special precautions to protect yourself and your family members.


Chemotherapy is a powerful cancer treatment that can lead to significant side effects. Chemotherapy works by targeting fast-growing cells. This is because cancer cells tend to reproduce quickly. The three goals of chemotherapy are to cure cancer, control cancer, and provide palliative care. 

A Word From Verywell

If you have received chemotherapy as part of your cancer treatment, you are well aware of both the benefits as well as the drawbacks. Undergoing a round of chemotherapy is exhausting, so seek out support where you can. Talk with your doctor if you experience side effects, and never hesitate to ask questions. 

Frequently Asked Questions

  • Is there a limit to how much chemotherapy you can have?

    The length of your treatment will depend on several factors, including your type of cancer, how advanced it is, your overall health, and how your body is responding to the current treatment. There is no set time limit on chemotherapy treatment. Talk with your medical team about the right treatment schedule for you.

  • What happens between my chemotherapy appointments?

    Between your chemotherapy appointments, you will continue to see your medical team and undergo testing to determine if the current treatment is effective. The time between your appointments is also a time to rest and allow your body to recover from the treatment. If you plan to continue working throughout your chemotherapy treatment, talk with your medical team about what to expect and how best to adjust your workload based on your treatment plan and prognosis. 

  • What happens to my DNA during chemotherapy?

    Chemotherapy is able to destroy cancer cells by targeting and changing their DNA. By damaging the DNA of the cancer cell, chemotherapy can cause the cell to die and stop reproducing. 

6 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.
  1. American Cancer Society. Chemotherapy side effects.

  2. American Cancer Society. How chemotherapy drugs work.

  3. American Cancer Society. Chemotherapy safety.

  4. American Cancer Society. How is chemotherapy used to treat cancer?

  5. American Cancer Society. Getting oral or topical chemotherapy.

  6. American Cancer Society. Getting IV or injectable chemotherapy.

By Carrie Madormo, RN, MPH
Carrie Madormo, RN, MPH, is a health writer with over a decade of experience working as a registered nurse. She has practiced in a variety of settings including pediatrics, oncology, chronic pain, and public health.