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Diarrhoea is the frequent passing of loose or watery stools, and/or the need to pass motion more often than usual. You may or may not experience pain or discomfort, but severe and persistent diarrhoea can cause complications such as dehydration and imbalanced electrolytes, which are life-threatening if left untreated. It is therefore advisable for you to inform your doctor or nurse early, if you develop diarrhoea.


Causes of Diarrhoea

  • Some cancers (e.g. colon cancer, pancreatic cancer)
  • Surgery to the intestines or pelvis
  • Chemotherapy (e.g. 5-FU, irinotecan)
  • Immunotherapy (e.g. pembrolizumab, nivolumab)
  • Radiation therapy especially to pelvis or abdomen
  • Graft versus host disease (side effect of bone marrow transplantation)
  • Anxiety or stress
  • Some medications (e.g. antibiotics, laxatives)
  • Some herbal supplements (e.g. milk thistle, ginseng)
  • Overflow of intestinal liquids around stool that is partially blocking the intestine
  • Other conditions unrelated to cancer (e.g. irritable bowel disease, viral or bacterial infections, lactose intolerance, thyroid overactivity)

What you need to look out for

  • Frequent urge to pass motion
  • Passing of loose or watery stools
  • Nausea or vomiting
  • Abdominal bloating, pain or cramps
  • Fever
  • Blood in stools
  • Signs of dehydration (e.g. dizzy, dry mouth or skin, dark-coloured urine, fatigue)


How it can be treated

Your doctor will ask you further questions (e.g. when the diarrhoea started) and conduct a physical examination, to determine the cause of your diarrhoea. Your doctor may also order for further investigations (e.g. stool investigations or imaging scans) if needed. Treatment for diarrhoea depends on its cause, as well as any symptoms or complications that you have. For instance, your doctor may adjust your chemotherapy regimen if you develop severe diarrhoea from chemotherapy. Anti-diarrhoeal medications (e.g. loperamide, lomotil) may also be prescribed, or you may need to have fluids infused into your vein if you are dehydrated.


What you can do

Besides taking note of the frequency and appearance of your stools, the following are some of the do’s and don’ts to help you to manage diarrhoea:


  • Take anti-diarrhoeal medications as prescribed by your doctor
  • If you are on laxatives or other medications that may cause diarrhoea, discuss with your doctor about stopping the medications

  • Avoid herbal supplements as some may cause diarrhoea

Fluids and nutrition

  • Drink plenty of water (unless advised not to do so by your doctor), to replenish fluids lost through diarrhoea. Mild, clear fluids such as clear soup is preferred
  • Take small frequent meals that are easy to digest, bland and low in fibre (e.g. porridge, white fish, soup noodles)
  • Take foods or drinks that replenishes potassium and sodium lost through diarrhoea (e.g. sports drinks, broth, oral rehydration salts), unless advised not to do so by your doctor 
  • Wash fruits and vegetables thoroughly before consumption

  • Avoid foods and drinks that can aggravate diarrhoea or cause irritation or cramping:
    - High fibre foods (e.g. beans, nuts)
    - Raw foods
    - Gas forming foods (e.g. broccoli)
    - Fried, greasy or oily foods
    - Acidic drinks (e.g. citrus juice)
    - Carbonated drinks
    - Alcoholic or caffeinated drinks 
    - Milk or milk-based products
    - Overly spicy foods

Personal hygiene

  • Wash your hands with soap and water after using the toilet, and before meals
  • Maintain a clean and hygienic environment. If needed, you can place a protective sheet on your bed or chair to prevent it from being soiled

Care of your skin

  • Frequent skin contact with stools may cause your anal area to become inflamed and uncomfortable. Be sure to clean your skin gently with water and use a soft cloth to dry gently after toileting
  • Apply barrier cream at the anal area to reduce skin irritations
  • Sit in a tub of warm, salt water to reduce discomfort at the anal area


When to call your cancer care team

Please inform your doctor or nurse if you notice symptoms of diarrhoea, if your diarrhoea does not improve despite treatment, or you develop the following symptoms that may indicate worsening or complications of the condition:

  • Uncontrollable diarrhoea
  • Fever
  • Blood in your stools
  • Weight loss of more than 2kg after diarrhoea starts
  • Vomiting and difficulty in keeping fluids down
  • Dark-coloured urine or not being able to urinate for 12 hours or more
  • Dizziness
  • Severe abdominal pain or cramps, or pain lasting 2 days or more
  • Abdominal bloating or swelling

If you have any questions regarding the above, please call the Cancer Helpline at +65 6225 5655 or approach your doctor or nurse for further details.

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The above contents are made available as part of TEMASEK FOUNDATION-ACCESS (Accessible Cancer Care to Enable Support for Survivors) PROGRAMME, a holistic care programme to support cancer patients during their care and recovery journey.

The contents have been approved by the Cancer Education Information Service, National Cancer Centre Singapore (NCCS), for people with cancer and their families and caregivers. However, this information serves only as a guide and should not be used as a substitute for medical diagnosis, treatment or advice. For specific medical conditions, please seek expert medical advice from your healthcare team.

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