Adverse effects of Chemotherapy

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Chemotherapy agents are distributed throughout the body; therefore, the side effects may affect the entire body and not just the area where the tumour is located. The effects vary between patients and depend on the type of chemotherapy. Most of the side effects gradually disappear after completing the treatment, although permanent damage may occur sometimes.


Thermometer with a danger signal indicating fever

Can appear as a direct side effect of the drugs administered during chemotherapy. It generally appears in the first few hours after they are administered and disappears quickly. It may also be associated with infections that arise because the patient’s defences are lowered by the actual treatment (immunosuppression); in this case, the patient needs to receive antibiotic therapy. 

If the patient develops a fever of above 38 °C, especially if it is accompanied by a cough with purulent phlegm, fatigue, pain or blood when urinating, catheter insertion site inflammation or any other related symptoms, they should discuss it with their healthcare team as a matter of urgency.

Inflammation of the mucous membranes (mucositis)

Woman with a sore on her tongue

Mucositis is inflammation of a mucous membrane and can produce painful sores and ulcers. It usually affects the oral mucous membrane, particularly the lips, tongue, palate and throat; although it can also occur in other areas, such as the anal, vulvar or vaginal mucous membranes.

If patients notice pain or changes in their mouth during chemotherapy, they should discuss it with their healthcare team.


  • Use toothbrushes with soft bristles and toothpastes with a high fluoride content.
  • Maintain good oral hygiene. Use a bicarbonate solution, salt water, thyme water or an alcohol-free mouthwash.
  • Use a lip balm or cocoa butter to keep lips hydrated.
  • Drink water in small sips throughout the day.
  • It is preferable to eat soft foods that are cold or at room temperature.


  • Eating dry and irritating foods (pepper, citrus fruits, etc.).
  • Using floss or interdental brushes.
  • Smoking and irritating drinks such as alcohol or coffee.
  • Professional dental cleaning procedures and tooth extractions.

Nausea and vomiting

Person with sweat, nausea and vomiting next to a toilet

Nausea and vomiting are the most common side effects of chemotherapy and can even appear despite taking medicines to prevent them. It is important to remember that each course of chemotherapy is specific to each patient and the frequency and intensity of these symptoms depend on the treatment and each patient’s individual sensitivity.

Therefore, before starting treatment, the healthcare team will inform patients about the chances of experiencing these side effects and the most suitable medicines for preventing them. Besides the drugs used to prevent vomiting and nausea (antiemetics), antianxiety agents and relaxation techniques can also help reduce the patient’s overall level of anxiety.


  • Eat in a relaxed, pleasant environment.
  • Patients should divide their daily intake into small amounts, eating 5–6 times a day.
  • Eat easily digested foods that are soft, have mild flavours and easy to prepare; for example, yoghurt, fresh cheese, flan, custard, cottage cheese, fruit sorbets, ice cream, jelly, toast, biscuits, sandwiches, omelettes, boiled eggs, chicken, pasta, boiled or mashed potatoes.
  • Savoury foods are generally tolerated more easily.
  • Eat dry foods in the morning such as biscuits or toast.
  • Meals should be at room temperature or cool, as hot meals may provoke the appearance of nausea.
  • Drink liquids apart from meals to avoid feeling too full.
  • Drink room temperature or cold drinks in small sips.
  • Rest for at least an hour after each meal, preferably while seated.
  • Prepare meals in advance and store them in individual containers in the freezer, these will be easy to reheat on days when the patient does not feel like cooking.


  • Cooking or preparing meals when the patient has nausea.
  • Foods with strong, pungent odours.
  • Acidic, spicy or highly seasoned foods.
  • Fatty foods (fried meals, rich sauces, fatty cheese, whole milk, etc.) as they hinder digestion.
  • Clothes that place pressure on the stomach.
  • Lying down after eating.


Woman with bowel problems by the toilet

If the chemotherapy affects cells lining the intestine, it may start to function differently. Consequently, the intestine loses its ability to absorb water and nutrients, which leads to diarrhoea. The healthcare team will prescribe medicines that prevent diarrhoea from appearing or stop it as soon as possible. Following an astringent diet based around low-fibre foods (e.g., rice, boiled fish, baked apples, etc.), drinking liquids slowly, avoiding milk and dairy products, and abstaining from irritating drinks such as coffee or alcohol can all help control diarrhoea. Sometimes it is severe due to the duration and number of daily bowel movements. If this happens patients must contact their healthcare team, so they can prescribe the most appropriate treatment to prevent dehydration.


  • In the first few hours after the onset of diarrhoea, ideally patients should fast completely (eat nothing) to give the intestine time to rest.
  • After 2–3 hours, they should progressively start drinking liquids in small sips: water, infusions (camomile, lime blossom tea, mint tea), juices without pulp and only a little sugar (apple, carrot), rice or carrot water and isotonic drinks.
  • Substitute cow’s milk with lactose-free milk or rice milk.
  • When the diarrhoea starts to subside, introduce small amounts of fat-free solid foods that are easily digested: boiled rice, rice with carrots, mashed potato, grilled or boiled white meat or white fish, cooked ham, apple purée, or grated and browned apple or quince.
  • Eat steamed, boiled or grilled foods.
  • Eat often and in small amounts.
  • Consume foods with a high potassium content (ripe banana, peaches in syrup, apricots, etc.).


  • Fried foods and stews, irritating condiments (e.g., pepper, paprika, nutmeg), red meats, orange juice or acidic fruits.
  • Foods that cause gases (cabbage, cauliflower, broccoli, peppers, raw onion) and raw vegetables or pulses.
  • Coffee, chocolate and alcoholic drinks.
  • Fatty foods (avocado, olives, industrial bakery products).
  • Patient should not take antidiarrhoeal agents without discussing them with their healthcare team.


Standing person with abdominal pain

Constipation is defined as defecating less than twice per week and the consistency of stools changes as they become hard and cause pain when expelled from the body. It is the most common intestinal complication in cancer patients and affects up to 40% when the disease is in an advanced stage and 90% of patients who take morphine, codeine or thebaine (opiates) to alleviate pain or cough. Constipation may highlight a more serious problem that requires further tests, so patients should discuss any symptoms of constipation or changes in their stools with their healthcare team.


  • Drink more liquids than normal.
  • Eat more high-fibre foods (e.g., wholemeal bread or cereals, fruits, vegetables, pulses).
  • Stimulate intestinal motility:
    • On an empty stomach, consume a spoonful of olive oil, a glass of warm water, infusions of mint tea, camomile or lemon balm, or orange juice with its pulp, coffee or 2–3 plums.
    • Drink cold liquids (water or juices) followed by hot liquids (coffee with milk or infusions). Drink milk and eat citrus fruits.
  • Take non-fermentable fibre supplements such as flax seeds.
  • Complete gentle exercise on a regular basis, for example, walk 30 minutes a day.
  • Try to maintain a fixed schedule for going to the toilet in order to train the bowels.
  • Adopt a position that favours the effort made by the abdominal wall and try to relax.
  • Massage the abdomen gently in a clockwise direction.


  • Strong and spicy condiments (pepper and chillies).
  • Foods with a high tannin content (quince, tea, red wine and apple).
  • Delaying performing bowel movements.
  • Do not take laxatives, suppositories or enemas without discussing it with the healthcare team.

Loss of appetite or anorexia

Closed stomach, lack of appetite and anorexia

This is when patients neither feel hungry nor do they wish to eat or try any foods.


  • Eat small portions and at least 4 or 5 times a day.
  • Enrich meals in order to provide maximum nutritional benefit:
    • Soups and purées: small portions of cheese, chopped boiled egg, croutons, diced ham, nuts, cream, butter, powdered milk, oatmeal or olive oil.
    • Vegetables: uncooked olive oil, béchamel sauce, mayonnaise, sautéed ham, nuts.
    • Rice dishes: tomato sauce, egg yolk, sautéed cured ham, garlic or onion.
    • Pasta: cream or tomato sauces, Parmesan cheese, bacon or butter.
    • Desserts: sugar, honey, jam, cream, chocolate, powdered or condensed milk, nuts, yoghurt with comport or milkshakes.
  • Prepare aesthetically attractive meals.
  • Patients should capitalise on the periods when they have the most appetite, for example at breakfast time, to eat a more complete intake.
  • Try to eat in a relaxed, pleasant environment. 


  • Heavy, greasy or fried meals and foods that produce gases.
  • Repugnant or unpleasant smells when eating.

Dry mouth (xerostomia)

Dryness of mouth

Xerostomia is dry mouth. It occurs when the salivary glands do not produce enough saliva. It is a subjective feeling. Given that we need saliva to chew, swallow, taste and talk, these activities may be more difficult in the case of dry mouth.


  • Pay great attention to oral hygiene. Use toothbrushes with soft bristles and toothpastes with a high fluoride content.
  • Use a bicarbonate solution, salt water, thyme water or an alcohol-free mouthwash.
  • Drink small amount of liquid frequently (acidic fruit juices, infusions with lemon, water with aromas, bicarbonated drinks).
  • To stimulate saliva or to moisten the mouth, chew pieces of fruit (pineapple) or sugar-free xylitol chewing gum, or suck ice cubes or caramels.
  • Eat soft, ground foods in broths or sauces: flans, custards, ice cream, yoghurt, soups, stews, juices, fruits in syrup or compotes.
  • Dress with lemon or vinegar.
  • Oral moisturisers (artificial saliva) can provide a useful substitute.


  • Dry, fibrous foods (nuts, biscuits, toast, grilled meats or fish, etc.) and oily and thick foods that require large amounts of saliva to chew and swallow.
  • Highly seasoned and salty foods.
  • Alcohol and alcohol-based mouthwashes.

Altered sense of taste (dysgeusia)

Disgruntled person sticking out tongue due to taste disturbance

This refers to a distortion in the taste of certain foods. Patients may notice some meals have less taste or discern a metallic or bitter taste (especially with high-protein foods such as meat and fish). Changes in the sense of taste can result in a loss of appetite, weight loss and an aversion to food. Patients should tell their healthcare team if they experience an abnormal sense of taste that affects their ability to eat.


  • Prepare meals that look appetising and smell pleasant.
  • Use mouthwashes before eating.
  • Chicken, turkey and eggs are usually better tolerated than red meat as they are less pungent.
  • Patients that perceive a metallic taste should replace their usual cutlery with plastic utensils.
  • Use mild spices or condiments when preparing meals.
  • Serve food at room temperature (it produces less smell).


  • Foods with pungent or strong odours such as cabbage and oily fish (e.g., sardines, salmon).
  • Ambient smells and areas where food is cooked.

Bone marrow alterations

The bone marrow is a tissue found inside certain bones that produces blood cells such as red blood cells, leucocytes and platelets. These cells divide rapidly which makes them very sensitive to the effects of chemotherapy. The loss of blood cells (red and white blood cells) is of particular importance because it influences immunoprotective mechanisms and oxygen transport.

Decreased immune system cells seen under the microscope

Low immune system (neutropaenia). Neutropaenia is an abnormally low number of white blood cells, which can favour the appearance of infections that manifest with fever.


  • Skin is usually more sensitive and vulnerable to infections, so it is important to incorporate routine hygiene, hydration and sunscreen habits for both the face and body.
  • Wash hands before handling foods and after going to the toilet.
  • Keep nails clean and short.
  • Change toothbrushes at least every 3 months.


  • Sharing food utensils, drinks and personal hygiene items.
  • Contact with faeces from pets.
  • Patients should not get vaccinations without first discussing them with their healthcare team.
  • Insofar as possible, avoid direct contact with people who have an infectious condition (flu, measles, etc.).
Blood test tube with a low red blood cell count or anemia

Low red blood cell count (anaemia). Anaemia is a fall in haemoglobin and haematocrit values in blood which manifests as tiredness, weakness or intense fatigue.


  • Maintain a relaxed lifestyle and avoid stressful situations or activities that require a significant physical exertion.
  • Patients should ensure they get enough rest and restful sleep at night.
  • Complete some physical exercise each day, inasmuch as possible and without overexerting.
Decreased platelets

Low platelet count (thrombocytopaenia). This a low number of platelets in the blood and it can cause the appearance of bruising and bleeding.


  • Take care when handling sharp or cutting objects.
  • Use an electric shaver.
  • Use a soft-bristled toothbrush and lip balm or cocoa butter to prevent cracked lips and dryness.


  • Waxes and razor blades.
  • Traumas and wounds. Wear closed-toed shoes to avoid falls.
  • Constipation.

Hair loss (alopecia)

Person with alopecia

Alopecia occurs because chemotherapy agents destroy hair follicles and therefore cause hair loss. Chemotherapy does not always result in hair loss as it depends on the type of drugs being used. Patients may also experience generalised hair loss, i.e., it not only affects the scalp but other parts of the body such as the armpits, arms, legs, eyebrows, eyelashes, etc. Hair loss occurs 2–3 weeks after starting the treatment and is reversible. When the hair falls out, patients may feel discomfort in the scalp due to an inflammatory process. Two to three months after completing treatment, the hair will start growing again. It will be finer at first and have different characteristics than the original hair (different colour, curlier or straighter, etc.). These changes to the new hair may be temporary or permanent.


  • Hair care. Use mild shampoos and soft-bristled brushes. Only use ammonia-free dyes. It is a good idea to test how the hair reacts to the dye before full application.
  • Protect and care for the scalp. Apply sunscreen and wear a hat or head scarf for protection from the sun. Hydrate the scalp.
  • Adapt to the hair loss. If necessary, patients can cut or shave their hair. Always use an electric shaver to avoid cutting the skin.


  • Aggressive hair treatments.
  • Using a hair dryer.

Alterations affecting the skin and nails

Person scratching his face

Itchiness (pruritus), redness (erythema), dryness and flaking skin. These symptoms are not usually very significant, but they should still be monitored. If sudden or intense itchiness of the skin, rashes, hives or difficulty breathing appear, these could be signs of an allergic reaction that requires immediate medical attention. Patients may develop skin photosensitivity, in other words, the skin becomes more sensitive to sunlight and therefore more vulnerable to sunburn and colour changes such as sun spots. Nails may develop a very dark colour or vertical stripes, they could become brittle and break easily. 


  • Tell the healthcare team about any changes to the skin or nails.
  • Use factor 50 sunscreen and apply it every 2–3 hours when outdoors.
  • Wear hats for protection and avoid direct exposure to the sun between 12:00 and 4:00 pm.
  • Use neutral soaps (such as syndet bars or ones with a physiological pH) and lukewarm water when showering. Maintain skin hydrated.
  • Apply perfume-free and preservative-free, hypoallergenic moisturising creams after showering.
  • Avoid products that irritate the skin such as perfumed soaps, creams and strong detergents. Do not use exfoliants or products that scratch the skin.
  • Wear comfortable footwear and loose-fitting socks/tights.
  • Wear comfortable, loose-fitting clothes made with natural fibres.

Neurological alterations

Certain drugs can affect sensitivity, generally in the limbs. This symptom is normally described as tingling in the palms, fingers, soles of the feet or toes and it may even be painful. It can appear a few weeks after starting treatment. Depending on the intensity and/or patient tolerance, it may result in suspension of the treatment. This symptom improves slowly and gradually after suspending or finishing the chemotherapy.

Central nervous system in pain

Ciertos fármacos pueden producir una alteración de la sensibilidad, generalmente en las extremidades. Se describe como unos hormigueos en la palma y dedos de las manos y en la planta y los dedos de los pies, que pueden llegar a ser dolorosos. Pueden aparecer a las semanas del inicio del tratamiento. Según la intensidad y/o tolerancia, pueden suponer la suspensión del tratamiento. Estos síntomas presentan una mejoría lenta y progresiva tras el cese o finalización de la quimioterapia.


  • Protect the hands and feet from extreme temperatures (wear gloves and socks).
  • Use lukewarm water when showering, washing your hands or doing the washing up.
  • Wear loose-fitting clothes and comfortable footwear.
  • Avoid handling cold drinks or ones containing ice cubes and ice cream.

Alterations to fertility and sexual dysfunction

Symbol of female sexuality

Chemotherapy can affect the function of the ovaries and reduce normal production levels of female sex hormones. This can cause a series of symptoms similar to those observed in the menopause:

  • Irregularities in or disappearance of the menstruation (amenorrhoea).
  • Vaginal dryness due to decreased lubrication, which complicates sexual intercourse; loss of vaginal elasticity.
  • Hot flushes.
  • Insomnia and irritability.
  • Possible pain in the genital area or in other parts of the body.
  • Loss of sex drive.
  • Increased risk of urinary tract infections.


  • Women who wish to have children can freeze their eggs for use after finishing the treatment.
  • Most of the local symptoms can be improved by applying lubricants before sexual intercourse.
  • Use vaginal moisturises on a regular basis.
  • Discuss the situation with your partner openly and honestly.
Symbol of male sexuality

In men, chemotherapy can cause changes associated with decreased sperm production. In some cases, chemotherapy can result in sterility (temporary or permanent), loss of sex drive and erectile dysfunction.


  • There are several ways of preserving sperm for men who wish to have children in the future.
  • Discuss the situation with your partner openly and honestly.
  • Patients with a low platelet count (thrombocytopaenia) should ask their healthcare team whether sexual intercourse is appropriate.

Substantiated information by:

Albert Tuca Rodríguez
Aleix Prat Aparicio
Francesc Balaguer Prunes
Meritxell Mollà Armandà
Montserrat Valverde Bosch
Vanessa Vilas
Álvaro Urbano Ispizua

Published: 12 November 2018
Updated: 20 November 2018

The donations that can be done through this webpage are exclusively for the benefit of Hospital Clínic of Barcelona through Fundació Clínic per a la Recerca Biomèdica and not for BBVA Foundation, entity that collaborates with the project of PortalClínic.


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