chemo side effects that comes and goes

Overview

Chemotherapy (chemo) uses strong medicines to kill cancer cells. Because these medicines also affect some healthy cells, they can cause side effects. Many of these side effects are not constant — they can come and go. You may feel fine one day and tired or sick the next. These ups and downs are normal and often temporary. Knowing what to expect can help you feel more in control.

Yes. Most people who receive chemotherapy will experience at least some side effects, and side effects that come and go are very common. The severity and patterns differ from person to person.

Chemo side effects can affect anyone receiving chemotherapy, including people being treated for cancer and those who have finished treatment. They may be more noticeable in older adults, people with other health conditions, or those undergoing intensive treatment. Children can also experience them, though their care team will monitor closely.

Symptoms

Common symptoms

• Fatigue that comes in waves — you may feel wiped out for days, then have more energy
• Nausea (feeling sick to your stomach) and vomiting that can come and go
• Changes in taste or smell — food may taste metallic, strange, or like nothing at all
• Mouth sores or soreness that can flare and then heal
• Diarrhea or constipation that alternates or is unpredictable
• Numbness, tingling, or burning in hands or feet (called peripheral neuropathy)
• Skin changes, such as dryness, itching, or sensitivity
• Flu-like aches and fevers that can occur around treatment times
• Difficulty concentrating or 'chemo brain' — feeling foggy, forgetful, or slow

Symptoms in children

• Irritability or fussiness more than usual
• Mouth sores that make eating uncomfortable
• Changes in appetite and picky eating
• Sleepiness or low energy that fluctuates
• Upset stomach or nausea that may come in waves
• Changes in behavior or mood during treatment periods

Symptoms in older adults

• More severe and longer-lasting fatigue
• Falls or unsteadiness, especially from neuropathy or weakness
• Confusion or memory changes that come and go
• Dehydration more easily from diarrhea or vomiting
• Reduced appetite leading to weight loss
• Symptoms that are harder to tell apart from other health problems

Causes

Main causes

• Chemo medicines work by targeting fast-growing cells — cancer cells are fast-growing, but so are some healthy cells like those in your mouth, stomach, skin, hair, and bone marrow.
• When the normal cells are damaged, it causes side effects. As normal cells recover between treatments, side effects may ease or go away.
• The type and amount of chemo you receive plays a big role in which side effects appear and how they come and go.
• Your own body's repair and recovery process is another cause — side effects often follow the healing cycle of the healthy cells.

Risk factors

• The specific chemotherapy medicine or combination used
• Higher doses of chemo medicine
• Your overall health before treatment
• Your age — older adults may be more vulnerable
• Receiving chemo over a longer period
• Having another health condition such as diabetes, heart disease, or kidney disease
• Prior treatment with radiation or other cancer therapies

When to see a doctor

See a doctor urgently if:

• If you have any symptoms that could be an emergency — call your local emergency number immediately.
• If you have a fever, especially during the days after chemo, call your care team right away.
• If you can't keep fluids down due to vomiting or diarrhea, seek urgent help.
• If you have sudden weakness in your arms or legs, or difficulty speaking, get emergency care.

Book a routine appointment if:

• Tell your care team about any side effect at your next scheduled visit, even if it is mild or comes and goes.
• If you develop new symptoms between treatments, call the clinic or your cancer nurse more quickly.
• Ask for a plan to manage side effects before each treatment so you know what to do at home.

Diagnosis

There is no test for 'chemo side effects' as a whole. Instead, your care team evaluates you based on your symptoms, how you are feeling, your treatment history, and physical examinations. They will often check blood counts, kidney and liver function, and other lab values to understand what might be contributing to your symptoms.

Tests that may be done

• Blood tests to check red and white blood cells, platelets, and organ function
• Urine or stool tests if needed to look for infection or dehydration
• Physical exam to check for mouth sores, skin changes, or signs of infection
• Neurological check for tingling or numbness in hands and feet
• Discussion about your symptoms, severity, and how they change over time

What to expect at your appointment

Expect a thorough conversation about your symptoms — how they feel, when they occur, and whether anything helps. Your care team may ask you to keep a symptom diary. They might adjust your chemo schedule or add supportive medicines. It is a team effort, and your input is essential.

Treatment

Treatment for chemo side effects focuses on relieving symptoms so you can get through treatment with the best possible quality of life. Your care team will tailor a plan based on the side effects you are experiencing. They may adjust the timing or dose of chemo, add supportive therapies, and suggest lifestyle changes.

Self-care at home

• Rest when you need to, but try to keep moving with gentle activity like short walks on good days.
• Eat small, frequent meals rather than three large ones to help with nausea and appetite.
• Sip fluids throughout the day to stay hydrated, especially if you have vomiting or diarrhea.
• Use a soft toothbrush and gentle mouth rinses to help with mouth sores.
• Protect your skin with sunscreen and moisturizer if your skin gets dry or sensitive.
• Keep a daily symptom journal so you can spot patterns and share them with your care team.
• Ask for help with chores and daily tasks when fatigue is strongest.

Medical treatments

There are many effective medical ways to manage chemo side effects. These may include prescription medicines to prevent or reduce nausea and vomiting, medicines to improve low blood cell counts, prescription creams for skin problems, and treatments for nerve pain from neuropathy. In some cases, your care team may adjust your chemo dose or slow the treatment schedule. Always ask about the risks and benefits of any recommended approach.

When is surgery considered?

Surgery is not usually used for treating chemo side effects themselves. It is a treatment for cancer, not for managing symptoms. If you have a symptom that requires surgery — such as a serious infection or a blocked bowel — your care team will discuss it with you fully. For most side effects, supportive medicines and lifestyle changes are the main approach.

Living with this condition

Living with chemo side effects means planning your days around how you feel. Some days you will have energy; other days you will need rest. It is okay to adjust your plans. Give yourself permission to do less on hard days. Keep a list of favorite foods, distractors, and comforting activities for when you feel unwell.

Lifestyle tips

• Accept help from family and friends — you do not have to manage alone.
• Rest before and after treatments, especially when side effects are expected.
• Use relaxation techniques like deep breathing, meditation, or gentle music to help with anxiety and nausea.
• Keep an open line with your employer or school about your needs — you may be able to adjust your schedule.
• Avoid smoking and limit alcohol, as they can worsen many side effects.
• Talk to your care team before taking any supplements or over-the-counter products.

Diet and exercise

Eating well during chemo can be challenging, but a balanced diet helps your body recover. Try to eat protein-rich foods like eggs, fish, chicken, beans, and dairy as tolerated. Soft foods like soups, oatmeal, bananas, and mashed potatoes are easier on the mouth and stomach. Gentle exercise, like short walks or stretching, can reduce fatigue, improve mood, and help with constipation. Always check with your care team before starting any new activity.

Mental health and emotional wellbeing

It is normal for chemo side effects to affect how you feel mentally and emotionally. The uncertainty, physical discomfort, and changes to your routine can cause stress, sadness, fear, or worry. You may feel frustrated that your body is not cooperating. Please be kind to yourself. Talk to your care team about how you are feeling — they can connect you with a counselor or mental health support. You do not have to face this alone.

Prevention

You cannot always prevent chemo side effects, but many can be reduced or made easier to manage. Pregiving your body good support — rest, good nutrition, and staying hydrated — may help. Your care team also has strategies to prevent specific side effects, such as medicines to prevent nausea before it starts. The key is proactive communication with your care team.

Vaccines

Ask your care team about vaccinations, including the flu and COVID-19 vaccines. Cancer treatment can increase your risk of infections, so prevention is especially important. Make sure to discuss vaccine timing with them, as you may need to avoid live vaccines during treatment.

Screening programmes

Regular follow-up appointments and blood tests during and after chemo are a type of screening. They help catch problems early, such as low blood counts or organ changes, so they can be managed before they become serious. Your care team will arrange a survivorship care plan that includes check-ups for long-term effects.

Complications

If left untreated

• Dehydration from severe vomiting or diarrhea
• Infections from low white blood cells (a condition called neutropenia)
• Serious weight loss and poor nutrition
• Falls or injuries from weakness and neuropathy
• Delayed recovery between chemo cycles
• Worsening mental health, including depression or anxiety

Long-term outlook

The good news is that most chemo side effects are temporary and improve after treatment ends. Your care team has many tools to help you manage them, and you can learn to live with the ups and downs. Even when side effects are tough, people get through them — and on the other side, many regain their strength and quality of life. You are not alone, and you are stronger than you know.

Find support

International organisations

• Cancer Research UK ↗
• American Cancer Society ↗

Local organisations

• Your local hospital or cancer center · Ask your care team about local support groups and patient services

Helplines

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