The side effects of chemotherapy depend on the type of drug involved. Common side effects include infections, easy bruising or bleeding, and hair loss.

Chemotherapy kills regular cells, as well as cancer cells, and this is why side effects occur. Many people experience these adverse effects, but some people have few or none.

Below, we explore 11 of the more common side effects of chemotherapy.

Anatomical illustration pointing out the 10 most common chemotherapy side effects.Share on Pinterest
Medical illustration by Stephen Kelly

Common side effects of chemotherapy include:

However, just because these side effects are common, it does not mean that all people will experience them all.

A woman with side effects from chemotherapy for breast cancer and her daughterShare on Pinterest
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Cancer and the treatment of it can weaken the immune system.

Because chemotherapy kills healthy immune cells, it can make a person more vulnerable to infection. And because the immune system is weakened, any infections may last longer than usual.

Frequently washing the hands, avoiding anyone with an infectious illness, and seeking prompt medical care for signs of an infection or fever can reduce the risk of a serious illness.

Chemotherapy can cause a person to bruise or bleed more easily. Many people having chemotherapy experience this side effect.

Bleeding more heavily than usual can be dangerous. It is a good idea to take precautions, such as wearing gloves when gardening or cutting food. Also, take extra steps to prevent injuries such as falls.

Contact a doctor about any serious wounds or any injuries or bruises that seem to be healing slowly. The American Cancer Society (ACS) recommends contacting the cancer team immediately about any bleeding or unexplained bruising during cancer treatment or any blood in stool or urine.

Fatigue is a common symptom of chemotherapy, as well as some forms of cancer themselves.

This fatigue is different from the tiredness that most people feel. Chemotherapy fatigue may cause people to feel tired, weak, and slow. In addition, rest does not alleviate this fatigue as it would typical tiredness.

Fatigue typically lessens after treatment is complete, but not in all instances.

Chemotherapy can damage hair follicles, causing the hair to weaken, become brittle, and fall out. Hair will regrow, but it may be a different color or texture. This usually continues until the treatment ends, after which hair almost always regrows.

Here, learn more about hair regrowth after chemotherapy.

Nausea and vomiting can start suddenly. These issues may occur right after each chemotherapy session or days later.

Dietary changes, such as eating a bland diet, eating smaller, high-calorie meals, or avoiding certain foods, can help. Anti-nausea medications can also help, especially if a person experiences the side effects at predictable intervals, such as immediately after chemotherapy.

Neuropathy is nerve pain caused by damaged nerves. It often affects the hands and feet, causing tingling, numbness, and unusual burning sensations. Some people also experience weakness and pain.

Lotions containing lidocaine or capsaicin may help, but more research is necessary, the ACS notes.

Chemotherapy may trigger digestion problems because it can damage cells that help digestion.

Other side effects of chemotherapy, such as nausea, can force people to change their diets, but these changes may also cause or worsen constipation or diarrhea if they are sudden.

Eating plain, well-tolerated foods and avoiding those that irritate the stomach may help. And over-the-counter remedies for constipation, such as a stool softener or fiber supplement, can make bowel movements less painful.

In addition, being well-hydrated can reduce the severity of constipation and also prevent dehydration caused by diarrhea.

Chemotherapy can alter the immune system in ways that cause rashes and other skin changes. The drugs can also trigger skin changes directly.

Severe rashes can cause painful, intense itching. If a person scratches until their skin bleeds, there is a risk of infection. Moisturizing lotions and over-the-counter anti-itch creams may help.

Some people develop painful oral sores 1–2 weeks after having some forms of chemotherapy. The soreness can vary in severity, and the sores may bleed or become infected.

People with mouth sores should avoid eating or drinking things that can irritate the mouth, such as spicy foods, alcohol, and irritating mouthwashes.

A person can try using a nonabrasive toothpaste or a numbing gel. Some people also find relief from rinsing their mouths with warm saltwater. See a doctor for treatment if any sores are very painful or weeping.

Sometimes, chemotherapy can damage the lungs and make it harder to take in enough oxygen. Breathing issues can also result from some types of cancer.

Staying calm, sitting and propping up the upper body with pillows, and practicing pursed lip breathing may help. A doctor may prescribe medication if breathing problems continue.

Call 911, or otherwise contact local emergency services if anyone has:

  • breathing problems that start suddenly and do not improve
  • a bluish tint to their mouth, nail beds, or skin
  • chest pain
  • weakness or dizziness
  • difficulty speaking

Some side effects of chemotherapy can cause pain. For example, there may be:

  • pain in the mouth and throat, possibly due to oral sores
  • nerve pain
  • pain at the injection site
  • headaches

Pain can also occur as cancer progresses. The ACS encourages people to contact their cancer care team if they experience headaches or pain at an injection or catheter site.

If pain occurs, do not stop having the treatment before discussing this with a doctor. They may be able to help.

Some people experience rare side effects of chemotherapy. Some examples that may signal an emergency include:

  • Hypersensitivity: This involves the immune system reacting to the chemotherapy drug.
  • Extravasation: This is when chemotherapy drugs accidentally leak from a blood vessel into surrounding tissues. This can cause significant tissue damage.

The ACS recommends seeking immediate medical care if any of the following occur after chemotherapy:

  • a fever higher than a person’s cancer team advises, usually over 100.5–101°F
  • intense chills
  • unusual bleeding or bruising
  • an allergic reaction, which may cause swelling, a rash, or severe itching
  • pain at the injection or catheter site
  • intense headaches or other unusual pain
  • persistent diarrhea, vomiting, or both
  • blood in the stool or urine
  • difficulty breathing, in which case, someone should call 911

Chemotherapy can be an effective cancer treatment, but it can also have adverse effects.

Before starting the treatment, speak with the doctor about which side effects are most likely, how long they might last, and how severe they might be.

If side effects occur, the cancer care team may be able to help manage them. Treatments and coping techniques can ease and relieve many chemotherapy side effects.