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Cancer treatment side effects

Also called: Cancer treatment side effects, chemo side effects, radiation side effects

Tiredness, nausea, mouth sores, hair loss, infection risk, and other effects from chemotherapy, radiation, or other cancer treatments. Most can be eased, so tell your care team.

Fever during chemoCall your cancer team right away
CommonTiredness, nausea, low blood counts
MostGet better after treatment

Overview

Low white cells make infections dangerous.

Newer treatments like immunotherapy have their own side effects.

Symptoms

Common signs:

  • Side effects from chemo or radiation
  • Getting chemotherapy, radiation, or other cancer treatment

Less common

  • Nausea
  • Tiredness
  • Mouth sores
  • Hair loss

When to get medical care

Call 911Fever of 100.4°F or higher during chemo, chills, or trouble breathing: call your team or 911.
Get care todayCan't keep fluids down.
See a doctor soonNew or worse side effects.

Causes

Cancer treatments.

Does it spread or run in families?

  • Cancer isn't contagious. You can't catch it from someone.
  • Some cases run in families. Ask whether genetic testing makes sense for you.

Possible complications

Diagnosis

Your care team checks blood counts.

Tests

Tests, if needed:

  • Blood counts:

Treatment

Take care of yourself.

Self-care

  • Wash hands often
  • Eat small meals
  • Rinse mouth with salt and baking soda water
  • Rest and move gently

Medicines

Medicines that may help:

MedicineHelps withGood to know
Anti-nausea medicines
Nausea

OwieClear doesn't give doses: follow the label or your healthcare professional. Medicine names here are examples, not a full list.

Which doctor treats this

  • Start with your primary care provider (family doctor or internist).
  • They may send you to an oncologist (cancer doctor), often with a surgeon and a radiation doctor.

Living with it

  • Keep a simple diary of symptoms, triggers, and medicines to bring to visits.
  • Bring a list of your medicines and questions to each visit.
  • Ask for a survivorship care plan when treatment ends.
  • Gentle activity, like walking, can ease tiredness.
  • Long-term illness can affect mood. Tell your doctor if you feel down or anxious.

Support groups and helplines

Back to school, work, or sports

  • Most people can keep working or going to school.
  • Ask about changes that help, like extra breaks or a flexible schedule. Workers may be covered by the ADA. Students may get a 504 plan.

Pregnancy and breastfeeding

  • If you're pregnant or planning to be, tell your prenatal provider about this condition.
  • Some cancer treatments can harm a baby. Ask about saving eggs before treatment if you want children later.
  • Don't start or stop any medicine on your own. Some are safe in pregnancy and some need to be changed.
  • Ask before taking any pain reliever. The FDA advises avoiding ibuprofen and naproxen after 20 weeks unless your doctor says to.
  • Breastfeeding: Most medicines are fine, but ask. The NIH LactMed database lists what's known about each one.

For caregivers

  • Go to visits when you can and take notes.
  • Keep a list of medicines, allergies, and doctors in one place.
  • Learn the warning signs that need fast care.
  • Take breaks and ask for help. Caregivers need care too.

Outlook

Most effects fade.

Getting ready for your visit

Bring a list of your symptoms and medicines.

Questions to ask

  • Who do I call after hours?

Research studies

Research studies test new ways to find and treat health problems. Some are looking for volunteers. Talk with your doctor before joining one.

Search ClinicalTrials.gov for studies on Cancer treatment side effects

Sources

Last updated 2026-11-12.