What is Diarrhoea?

Diarrhoea is defined as a loose or watery stool with a bowel motion frequency of more than 3 times a day. Diarrhoea can be acute or chronic. The subtype of the diarrhoea determines investigation and management. Acute diarrhoea usually lasts a few days and sometimes up to 2 weeks. Chronic or persistent diarrhoea is generally defined as diarrhoea lasting more than 4 weeks. Diarrhoea can occur alone or together with other symptoms.


Diarrhoea symptoms commonly associated include:


The main reasons to see a doctor or a diarrhoea specialist are

  • Signs of dehydration (Dry mouth or loss of skin turgor, Extreme thirst, Little or no urination, Fatigue, dizziness or lightheadedness)
  • Persistent high fever
  • Diarrhoea frequency of >6 times per day
  • Blood in the stool
  • Severe abdominal pain

There are many different causes for diarrhoea, including:

  • Viruses. e.g Norovirus and Rotavirus most commonly.
  • Bacteria and parasites. e.g. Campylobacter, Salmonella species or parasites such as giardia.
  • Medications. Medications, such as antibiotics can cause diarrhoea.
  • Lactose and Fructose Intolerance
  • Artificial sweeteners. e.g. Sorbitol
  • Surgery. Patients post-surgery with short bowel syndrome or after gallbladder removal sometimes develop diarrhoea.
  • Other digestive disorders. e.g. Irritable bowel syndrome, Crohn’s disease, ulcerative colitis, celiac disease, microscopic colitis and small intestinal bacterial overgrowth (SIBO).

Your doctor or diarrhoea specialist will take a complete personal history via a series of questions on previous overseas travels, medications and dietary factors. Acute diarrhoea usually does not require further investigation though in severe cases, blood and stool tests may be helpful. In cases of chronic diarrhoea, further investigations including blood and stool tests, colonoscopy with colon biopsy, hydrogen-methane breath testing and imaging studies of the pancreas may be necessary to guide further management.


Episodes of acute diarrhoea are usually self-limiting and can be treated with over-the-counter medication. Symptomatic measures for diarrhoea should include oral rehydration salts (ORS) to avoid dehydration and reducing certain types of foods such as dairy(lactose) products to avoid aggravating the diarrhoea. Chronic diarrhoea treatment is dependent on the exact cause.