Managing side effects of cancer treatment

Practical, friendly tips for common side effects of cancer treatment: tiredness, nausea, mouth sores, hair loss, numbness and tingling, skin changes, low blood counts and "chemo brain." Report them, don't just endure them.

7 min read · last reviewed September 30, 2026

When people think about cancer treatment, side effects are often their biggest worry. Here's the reassuring part: side effects depend on the kind of treatment, and everyone is different. Many people have fewer side effects than they expected, and there are good ways to prevent and treat most of them.

The most important tip on this page: report side effects, don't just put up with them. Your team can only help with what they know about. Sometimes a small change to your medicines or your treatment makes a big difference.

Tiredness (fatigue)

Cancer-related tiredness is not ordinary tiredness. It may not get better with sleep, and it can come and go. It is one of the most common side effects.

What helps:

• Keep moving, gently. It sounds backwards, but regular light activity, such as a daily walk, is one of the best ways to ease cancer-related tiredness. Start small and build up.
• Plan your day. Do the most important things when you have the most energy. Rest between activities.
• Keep naps short so you can sleep at night.
• Accept help with shopping, cooking and cleaning.

Tell your team if tiredness is severe or suddenly gets worse. It can have causes they can treat, such as a low red blood cell count (anemia), poor sleep, pain or low mood.

Nausea and vomiting

Many treatments no longer cause much sickness, thanks to good anti-nausea medicines.

What helps:

• Take your anti-nausea medicine exactly as prescribed, including before you feel sick. It works best when it prevents nausea.
• Eat small meals or snacks often, rather than big meals.
• Try plain, dry foods like crackers or toast, and cool foods with little smell.
• Sip fluids through the day.

Call your team if you can't keep fluids or medicines down, or you are vomiting often. There are other medicines they can try.

Mouth sores and mouth changes

Some treatments can make your mouth sore or dry, or change how food tastes.

What helps:

• Keep your mouth clean. Brush gently with a soft toothbrush after meals and at bedtime.
• Rinse often with a simple rinse your team recommends, such as salt or baking soda in water. Avoid mouthwashes with alcohol.
• Choose soft, moist foods and avoid very spicy, salty, acidic or crunchy foods.
• See your dentist before treatment, if your team suggests it.

Call your team if mouth sores are painful or stop you from eating or drinking.

Hair loss

Some chemotherapy medicines cause hair loss, but many don't. If hair loss happens, it usually starts a few weeks after treatment begins. It usually grows back after treatment ends, though it may be a different texture or colour at first.

What helps:

• Ask whether your treatment is likely to cause hair loss, so you can plan.
• Some people cut their hair short before treatment, so the change feels less sudden.
• Ask about scalp cooling ("cold caps"). For some treatments, it can reduce hair loss.
• Protect your scalp from sun and cold with a hat or scarf.
• Wigs, scarves, hats, or none at all: whatever makes you feel like you is the right choice.

Numbness and tingling (neuropathy)

Some medicines can affect the nerves in your hands and feet. You might feel tingling, numbness, burning, or have trouble doing up buttons.

What helps:

• Tell your team early. They may adjust your treatment to stop it from getting worse.
• Protect your feet. Wear shoes that fit well, and check your feet for cuts.
• Prevent falls. Use night lights and remove loose rugs.
• Test water temperature with your elbow or a thermometer, because you may not feel heat as well.

Skin and nail changes

Radiation can make skin in the treated area red, dry or sore. Some targeted therapies cause rashes. Chemo can make skin more sensitive to the sun.

What helps:

• Wash gently with mild soap and lukewarm water, and pat dry.
• Use a gentle, unscented moisturizer, or the one your team recommends.
• Protect your skin from the sun: shade, clothing and a hat.
• Ask before putting anything on skin that is being treated with radiation.

Low blood counts

Many treatments lower blood counts for a while. Your team checks them with blood tests.

• Low white blood cells mean a higher risk of infection. Wash your hands often and avoid people who are sick. A fever of 38.0 °C (100.4 °F) or higher during chemo is an emergency. Call your cancer centre's 24-hour line or go to emergency right away. See Fever and when to get help.
• Low red blood cells (anemia) can make you tired, pale or short of breath.
• Low platelets can cause easy bruising or bleeding. Use a soft toothbrush and an electric razor, and report bleeding.

"Chemo brain"

Some people notice trouble remembering things, finding words or focusing during or after treatment. This is sometimes called "chemo brain," though it can happen with other treatments too. For many people it improves over time.

What helps:

• Write things down, or use phone reminders and a calendar.
• Do one thing at a time, and do harder tasks when you feel most alert.
• Keep active and get enough sleep.
• Tell your team if it bothers you. Tiredness, poor sleep, low mood and some medicines can make it worse, and some of these can be treated.

A word about "putting up with it"

Many people try to be brave and not "complain." Please don't. Reporting side effects is part of good care, not a sign of weakness. Keep a simple diary of how you feel each day, and bring it to appointments.

Something you can do today: Start a side-effect diary. Note the date, what you felt, how bad it was (0 to 10) and what helped.

Questions to ask your care team

• What side effects are most likely with my treatment? When might they start?
• What can I do to prevent them?
• What medicines should I have at home, and how do I take them?
• Which side effects should I call about right away?
• Is scalp cooling an option for me?
• Can I see a dietitian, physiotherapist or other specialist for help?

This article is general information, not medical advice. Talk with your health care team about your own situation. In an emergency, call 9-1-1 or your local emergency number.

In an emergency, call 9-1-1 or your local emergency number.

General information, not medical advice. It does not replace your own care team. If you think you or someone else is having a medical emergency, call 9-1-1 or your local emergency number. If you are in crisis or thinking about suicide, call or text 9-8-8 (Canada and the US).

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