Chemotherapy is a treatment that uses drugs that kill rapidly dividing cancer cells to prevent them from growing and making more cells.

Many chemotherapy drugs have adverse effects that can be severe. However, if a doctor recommends a person have chemotherapy, this usually means that the benefits are likely to outweigh any adverse effects.

An individual will often undergo chemotherapy as part of an overall treatment plan, which may also include surgery and radiation therapy. These treatments are effective in many cases of cancer. However, their effectiveness will often depend on the type and stage of cancer, among other factors.

Talking with a doctor will help a person understand what to expect from chemotherapy.

Read on to find out more about chemotherapy and what it involves.

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Photo editing by Stephen Kelly; Glasshouse Images/ Getty Images

A healthy body constantly replaces cells through a process of dividing, growing, and dying. When cancer occurs, cells reproduce uncontrollably and do not die when they should.

As a part of the body produces more and more of these abnormal cells, they start to occupy the space that useful cells previously took up.

Chemotherapy drugs interfere with a cancer cell’s ability to divide and reproduce. Drugs vary in how they work. Different drugs attack cancer cells at different phases in the cell life cycle.

Treatment can attack rapidly dividing cells throughout the body or only specific substances or parts of cancer cells.

In a chemotherapy treatment, a doctor may give a person a single drug or a combination of drugs at a time.

Chemotherapy is an invasive treatment that can have severe adverse effects both during the therapy and even sometime after. This is because the drugs cannot differentiate between healthy and cancer cells and tend to target both.

However, individuals with certain types of cancer who receive early chemotherapy treatment may achieve a complete cure. This makes the side effects worthwhile for many. Also, most of the unwanted symptoms go away after treatment finishes.

Receiving chemotherapy can be difficult, and 1 in 4 people with cancer have depression.

A 2016 study found that depressive symptoms are common in people undergoing chemotherapy and that marital and family support help manage these symptoms.

Some individuals may find it helpful to talk with a counselor about the mental and emotional aspects of cancer and chemotherapy.

How long does it last?

The doctor will make a plan with an individual that specifies when treatment sessions will occur and how many sessions the individual will need.

A person may receive chemotherapy for a specific amount of time or for as long as it works.

A course of chemotherapy treatment usually lasts 3–6 months, depending on the type of drug and stage of cancer. Doctors typically administer chemotherapy in cycles, with rest periods between 1–4 weeks. Cycles have rest periods in between to allow a person’s body to recover.

An individual might have treatment on one day, followed by 1 week’s rest, then another 1-day treatment followed by a 3-week rest period, and so on. A person may repeat this schedule several times.

Learn more about how long chemotherapy takes here.

Blood tests

Blood tests assess a person’s health and ensure that they will be able to cope with possible side effects.

Liver health: The liver breaks down chemotherapy chemicals and other drugs. Overloading the liver could trigger other problems. If a blood test detects liver problems before treatment, a person may have to postpone treatment until the liver recovers.

Complete blood count: Doctors will check a person’s red blood cell (RBC), white blood cell (WBC), and platelet count before treatment. If these are low, a person may need to wait until they reach healthy levels before starting chemotherapy.

It is essential to have regular blood tests throughout the treatment period to ensure that blood and liver functions remain as optimal as possible and to monitor the effectiveness of the treatment.

How is the dose given?

There are various ways of taking chemotherapy. These include:

  • oral, as tablets, liquid, or capsules
  • intravenous (IV), as an injection or infusion into a vein and directly into the bloodstream
  • topical, onto the skin
  • through an injection, as a shot in a muscle or right under the skin
  • intrathecal, injected into a fluid-filled space between the tissues covering the brain and the spinal cord, for cancers that reached the cerebrospinal fluid
  • intraperitoneal, directly into the peritoneum, or the covering of the surface of the abdomen surrounding internal organs, such as the stomach and the intestines
  • intra-arterial, injected to an artery that goes directly to the cancer

Most people will receive chemotherapy in a clinic or a hospital, but sometimes, they can take it at home. A person who receives chemotherapy drugs at home should take the dose exactly as prescribed. If they forget to take a dose at the right time, they should contact their doctor immediately.

They will still need to make regular visits to the hospital for doctors to check their health and response to treatment.

A person receiving drugs through an IV receives it through a needle or other instruments, such as:

  • Catheter: A doctor places one end of a thin, soft tube in a large vein near the heart, and the other end stays outside the body.
  • Port: Ports are small round disks implanted underneath the skin and remain there until a person finishes their treatment. A catheter connects the port to a vein near the heart through the chest, arm, or abdomen.
  • Pump: Healthcare professionals often attach these to catheters or ports for a more controlled release of drugs. Pumps can be surgically implanted under the skin or carried outside the body.

Chemotherapy can produce adverse effects that range from mild to severe, depending on the type and extent of the treatment. Some people may experience few to no adverse effects.

A wide range of adverse effects can occur, including:

1. Nausea and vomiting

Nausea and vomiting are typical side effects. Doctors may prescribe antiemetic drugs to help reduce the symptoms.

Ginger has bioactive compounds called gingerols and shogaols that have multiple benefits for chemotherapy patients undergoing therapy, according to a 2016 study.

2. Hair, nails, and skin

Chemotherapy drugs attack fast-growing cells, such as hair cells. This may cause some people to experience hair loss or cause their hair to become thin or brittle a few weeks after starting their treatment.

Wearing cooling caps can keep the scalp cool during chemotherapy treatment, which may help prevent or reduce hair loss. A 2019 study found that scalp cooling not only prevented hair loss but also caused faster recovery of hair volume after treatment.

Most, but not all, people find that their hair grows back once they have finished treatment. A counselor may offer advice about obtaining a hairpiece or another suitable covering during treatment.

Chemotherapy can also affect the skin and nails. Nail changes can include:

  • thinner, weaker nails
  • painful nail beds
  • dry, cracked skin in the cuticles
  • color changes
  • ridges or marks in the nails
  • lifting or falling off of nails
  • slow nail growth

The skin may become dry and sore. It may also become oversensitive to sunlight, which healthcare professionals call photosensitivity. People should take care in direct sunlight, including:

  • avoiding the sun around midday
  • using sunblock
  • wearing clothes that provide maximum protection

Here, learn which foods can help a person’s hair grow back.

3. Fatigue

Fatigue is among the most frequent side effects of chemotherapy. A person may experience this most of the time or only after certain activities.

To reduce fatigue, a person can consult a doctor about what the right balance of activity and rest is for them. In many cases, it is best to avoid total rest unless a doctor has instructed it.

Maintaining a level of physical activity may help with symptoms and may mean a person is able to carry on with everyday life as much as possible.

4. Hearing impairment

The toxins in some types of chemotherapy can affect the nervous system, leading to:

A person should report any hearing changes to the doctor.

5. Infections

WBCs help protect the body from infection. Chemotherapy can cause the number of WBCs to fall, weakening the immune system and increasing the risk of infections.

People should take precautions to reduce their likelihood of getting an infection. These include:

  • washing the hands regularly
  • keeping any wounds clean
  • following appropriate food hygiene guidelines
  • getting early treatment if they suspect an infection
  • avoiding contact with people who could have an infectious illness

A doctor may prescribe antibiotics to help reduce the risk.

Individuals with febrile neutropenia should also avoid exposure to soil. They may have to avoid gardening, digging, outdoor construction, and similar activities.

6. Bleeding problems

Chemotherapy can reduce a person’s platelet count. This means the blood will no longer clot as effectively.

The person may experience:

  • easy bruising
  • more bleeding than usual from a small cut
  • frequent nosebleeds or bleeding gums

If the platelet count falls too low, an individual may need a blood transfusion.

People should take extra care when engaging in activities such as cooking, gardening, or shaving, to reduce the risk of injuring themselves.

7. Anemia

Chemotherapy can cause RBC levels to fall, which will lead to anemia. Around 70% of people undergoing chemotherapy develop anemia.

Symptoms include:

Consuming extra iron may help the body make more RBCs. People can take in extra iron from their diet. Good food sources include:

Doctors may give blood transfusions to people experiencing severe or worsening symptoms of anemia.

8. Mucositis

Mucositis, or inflammation of the mucous membrane, can affect any part of the digestive system, from the mouth to the anus.

Oral mucositis affects the mouth. Symptoms can vary depending on the chemotherapy dose. It can make it painful to eat or talk, while some individuals experience a burning pain in their mouth or on their lips.

If bleeding occurs, it may mean a person has an infection or is at risk of one. It often appears 7–10 days after starting treatment and typically disappears a few weeks after treatment.

A doctor may prescribe medication to help prevent or treat it.

9. Loss of appetite

Chemotherapy, cancer, or both can affect how the body processes nutrients, which can lead to a loss of appetite and weight loss.

The severity of these side effects depends on the type of cancer and chemotherapy treatment, but a person usually regains their appetite after treatment.

Tips to resolve this include eating smaller, more frequent meals and consuming nutrient-rich drinks, such as smoothies, through a straw to help maintain fluid and nutrient intake.

People who find it too difficult to eat should speak with a doctor for advice.

10. Pregnancy and fertility

People often lose interest in sex during chemotherapy, but they usually regain it after treatment.


Some types of chemotherapy can reduce a person’s fertility. Often, this returns after treatment is over. However, people who wish to have children in the future may consider freezing sperm or embryos for later use.


Chemotherapy can have severe adverse side effects, and therefore, it may be best to avoid becoming pregnant while having treatment.

A doctor can advise on suitable birth control methods. Anyone who is pregnant or becomes pregnant during chemotherapy treatment should tell their doctor at once.

11. Bowel problems

Chemotherapy can also lead to diarrhea or constipation, as the body expels damaged cells. Symptoms often begin a few days after treatment starts.

A doctor may prescribe medications to help with diarrhea before treatment begins. If a person feels they are becoming dehydrated due to diarrhea, they should contact a doctor right away.

12. Cognitive and mental health problems

A 2021 study found that individuals who received chemotherapy had worse cognitive function 6 months after receiving chemotherapy.

Chemotherapy can also lead to difficulty with reasoning, organizing, and multitasking. Some people experience mood swings and depression.

The treatment itself and a person’s anxiety about the condition may also trigger or worsen these symptoms.

Types of chemotherapy include:

  • Alkylating agents: These affect the DNA and kill the cells at different stages of the cell life cycle.
  • Antimetabolites: These mimic proteins that the cells need to survive. When the cells consume them, they offer no benefit, and the cells starve.
  • Plant alkaloids: These stop the cells from growing and dividing.
  • Anti-tumor antibiotics: These stop the cells from reproducing. They are different from the antibiotics people use for infections.

There are many different classes of medication that doctors use in conjunction with chemotherapy, including monoclonal antibodies, immunotherapy, and targeted drugs.

A doctor will recommend a suitable option for an individual. They may recommend combining chemotherapy with other options, such as radiation therapy or surgery.

Factors determining the type of chemotherapy and how well it will work include the location, type, and stage of the cancer and a person’s age, overall health, and any existing medical conditions.

Learn how to know if chemotherapy is not working here.

The outlook for an individual receiving chemotherapy will depend largely on the type, stage, and location of the cancer and a person’s overall health. In some cases, complete remission is possible.

There can be adverse effects, however, and people may need to adjust their lifestyle or work routine during treatment. However, these usually resolve after treatment finishes.

Before starting treatment, a person may wish to discuss with the doctor:

  • why they are recommending chemotherapy
  • what the other options are
  • which types of chemotherapy are available
  • how much it will cost
  • what to expect in terms of adverse effects

They may also want to contact:

  • an insurance provider about covering the costs
  • their employer, if applicable, about how treatment may affect their work routine
  • family, friends, or caregivers about what to expect

A doctor can often put a person in touch with a counselor or support group, who may help.


I have known some people who declined chemotherapy when they had later stage cancer. Is this a good idea?


Each person’s situation is different. Nobody should make a decision without exploring all the available options. Having an honest, open discussion regarding outcome potentials and expectations with friends, family, and healthcare professionals is very important.

Alan Carter, PharmD

Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.