Many symptoms during treatment are not side effects. Find yours to see whether your treatment can cause it, and what to do.
Many symptoms during cancer treatment are not side effects. Tap the part of the body, then your symptom, to see whether your treatment can cause it and what to do.
Type your medicines in My treatment for answers about your own medicines.
Other causes: Viral infection, allergy, sinus infection.
Runny nose or mild sore throat, no fever
Manage at home
Other causes: Shingles is the chickenpox virus waking up, often when immunity is low.
Other causes: Poor sleep, dehydration, tension, eye strain, sinus.
Mild, eases with rest or paracetamol
Manage at home
Sudden severe headache, confusion, weakness, fits or change in vision
Go to emergency now
Other causes: Dry eyes, conjunctivitis, needing new glasses.
Watery or dry eyes
Manage at home
Other causes: Tooth decay, gum infection.
Mild sensitivity
Manage at home
Other causes: Mouth infection (thrush), dehydration, some other medicines.
Food tastes different, eating normally
Manage at home
Other causes: Acidity, eating too fast.
Short spells
Manage at home
Other causes: Not drinking enough, low blood pressure, low haemoglobin, low sugar.
Brief, on standing up quickly
Manage at home
Other causes: Ear wax, ear infection, age.
Other causes: Dry air, picking the nose, high blood pressure.
Other causes: Cold, acidity, overuse of the voice.
Mild, with a cold
Manage at home
Other causes: Mouth or throat infection (thrush), acidity, radiotherapy to the neck or chest.
Mild, eating soft food
Manage at home
Other causes: Acidity, muscle strain, chest infection.
Pain at rest, with breathlessness or sweating, or spreading to the arm or jaw
Go to emergency now
Other causes: Low haemoglobin, chest infection, fluid around the lungs, anxiety.
Other causes: Anxiety, fever, low haemoglobin, thyroid, tea or coffee.
Brief, after activity or worry
Manage at home
Other causes: Spicy food, painkillers, an empty stomach.
Mild, after food
Manage at home
Other causes: Chest infection, the cancer itself.
Other causes: Piles, a small tear (fissure), constipation, an abscess or fistula.
Mild pain with hard stools
Manage at home
Fever, a hot and swollen painful area, pus, or loose stools with blood
Go to emergency now
Other causes: Piles, a fissure, a stomach ulcer.
Other causes: Gas, constipation, acidity.
Mild, comes and goes
Manage at home
Other causes: Hepatitis, gallstones, other medicines.
Other causes: Low mood, pain, constipation, the cancer itself.
Eating less, weight steady
Manage at home
Other causes: Urine infection (common), not drinking enough.
Mild, after drinking little water
Manage at home
Other causes: Not drinking enough, loose stools or vomiting.
Other causes: Menopause, pregnancy, fibroids.
Periods irregular or stopped: mention at your visit
Manage at home
Other causes: Urine infection, kidney stones. Red medicines (doxorubicin) colour the urine without blood.
Other causes: Thrush (yeast infection), menopause.
Mild dryness
Manage at home
Other causes: Tiredness, worry, diabetes, other medicines.
Mention it at your visit; it is common and treatable
Manage at home
Other causes: Dry skin, allergy to a new medicine, jaundice, scabies.
Mild itch, no rash
Manage at home
Other causes: Sitting for long, injury, infection, low protein, lymph node swelling.
Both ankles mildly swollen by evening
Manage at home
One leg swollen, painful or red, or with breathlessness (possible clot)
Go to emergency now
Other causes: Menopause, infection, anxiety. Night sweats with fever or weight loss need checking.
Hot flushes
Manage at home
Other causes: Lymphoedema after lymph node surgery or radiotherapy, a clot near a PICC line or port.
Other causes: Infection or a clot around the line.
Other causes: Arthritis, strain, low vitamin D.
Mild, eases with paracetamol
Manage at home
Other causes: Muscle strain, posture, disc problems.
Back pain with leg weakness, numbness, or trouble passing urine or stools
Go to emergency now
Other causes: Diabetes, low vitamin B12, a pinched nerve.
Mild, daily tasks normal
Manage at home
Other causes: Weak muscles, low blood pressure, poor eyesight.
Other causes: Worry, pain, long naps, tea or coffee late in the day.
Occasional poor nights
Manage at home
Other causes: Tiredness, poor sleep, worry, low mood.
Mild: lists and routines help
Manage at home
Other causes: A cancer diagnosis itself; tiredness, pain, poor sleep.
Some low days
Manage at home
This information is general. If you are unsure, call or message the duty mobile. In an emergency, go to the nearest emergency department.
Written and medically reviewed by Dr Prathyusha Eaga, MD, DM (Medical Oncology). Last reviewed: 12 October 2026. Based on NCCN and ESMO guidelines.
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