Quick answer. Most diarrhoea in Singapore is caused by viral gastroenteritis or food poisoning and settles within a few days, while IBS, food intolerance and medications cause recurring loose stools. The biggest red flag is blood in the stool or signs of severe dehydration, which need urgent medical attention.
Diarrhoea, or passing loose, watery stools more often than usual, is one of the most common reasons people visit a GP or polyclinic in Singapore. In our hot, humid climate, food and water can spoil quickly, so a sudden bout after a hawker meal, a buffet or overseas travel is often acute gastroenteritis or food poisoning that clears on its own with rest and fluids.
Diarrhoea that keeps coming back or lasts more than two weeks is different and deserves a closer look. Conditions such as irritable bowel syndrome (IBS), lactose intolerance, certain medications, and less commonly inflammatory bowel disease (IBD) or coeliac disease can all be the cause. Knowing which symptoms point to something serious helps you decide whether to wait it out, see a doctor, or seek emergency care.
At a glance
| Likely cause | Typical features | What to do |
|---|---|---|
| Viral gastroenteritis | Sudden watery stools, cramps, sometimes vomiting, often after contact with a sick person | Rest, fluids and oral rehydration; usually settles in a few days |
| Food poisoning | Onset hours after a suspect meal, vomiting and cramps, may affect others who ate the same food | Hydrate; see a doctor if blood, high fever or severe symptoms |
| IBS | Recurring loose stools alternating with constipation, bloating, relief after passing motion | See a doctor for diagnosis and trigger management |
| Food intolerance (e.g. lactose) | Loose stools, gas and bloating after milk, dairy or specific foods | Identify and limit the trigger food; review with a doctor |
| Medication or antibiotics | Loose stools starting after a new medicine or course of antibiotics | Do not stop prescribed medicine on your own; ask your doctor |
Red flags: when to seek urgent care
Most diarrhoea is mild, but some signs mean you should not wait. Call 995 or go to the nearest emergency department if there are signs of severe dehydration or shock, such as confusion, fainting, a racing heartbeat, very little or no urine, sunken eyes, or cold, clammy skin.
- Blood in the stool, or black, tarry stools (a sign of bleeding higher up in the gut)
- Signs of severe dehydration: dizziness, no urine for many hours, very dry mouth, lethargy
- High fever or severe, constant abdominal pain
- Persistent vomiting so you cannot keep fluids down
- Diarrhoea lasting more than two weeks, or unexplained weight loss
Infants, the elderly and people with chronic illness dehydrate faster, so seek care earlier for them.
Gastroenteritis and food poisoning
Acute gastroenteritis, often from a virus such as norovirus or rotavirus, is the most common cause of sudden diarrhoea. It spreads easily through contaminated hands, food or surfaces and usually comes with cramps and sometimes vomiting. Food poisoning from bacteria like Salmonella or Campylobacter tends to start within hours to a day of eating contaminated food and may affect several people who shared the meal.
Both usually settle within a few days. The priority is fluids: sip oral rehydration salts (available at any pharmacy in Singapore), water or clear soups. Avoid sugary or very oily foods until you recover. See a doctor if you see blood, run a high fever, or cannot keep fluids down.
IBS and food intolerance
Irritable bowel syndrome is a common cause of recurring diarrhoea, often mixed with bloating, cramping and a sense of relief after passing motion. Symptoms may be triggered by stress, certain foods or large meals. While IBS is not dangerous, it can affect daily life, and a doctor can confirm the diagnosis and help you manage triggers.
Food intolerance, especially to lactose in dairy, is also common in Asian populations. If loose stools, gas and bloating reliably follow milk, ice cream or cheese, lactose may be the cause. Keeping a simple food and symptom diary helps you and your doctor spot the pattern.
Medications, antibiotics and infections
Many medicines can loosen the stool. Antibiotics are a common culprit because they disturb the normal gut bacteria, and in some cases this leads to a more stubborn infection that needs specific treatment. Other medicines, including some used for diabetes, heartburn and high blood pressure, can also cause diarrhoea. Never stop a prescribed medicine on your own; speak to your doctor about alternatives.
Travellers’ diarrhoea from contaminated food or water is common after trips around the region. Parasitic and bacterial infections can cause more prolonged diarrhoea, sometimes with blood or mucus, and may need stool tests and targeted treatment.
When diarrhoea becomes chronic
Diarrhoea lasting more than four weeks is considered chronic and should always be assessed. Causes include IBS, inflammatory bowel disease (Crohn’s disease and ulcerative colitis), coeliac disease, and, less commonly, problems with the pancreas or thyroid. IBD often comes with blood in the stool, abdominal pain, fatigue and weight loss, while coeliac disease is an immune reaction to gluten.
A doctor may arrange blood tests, stool tests and sometimes a colonoscopy to find the cause. Persistent diarrhoea with weight loss, blood, or a recent change in bowel habit, particularly after age 50, should be checked promptly.
Which specialist should you see?
Start with your GP or a polyclinic for acute diarrhoea; most cases need only fluids and reassurance. If diarrhoea is persistent, recurrent, bloody, or comes with weight loss, you should see a gastroenterologist, a doctor who specialises in the digestive system. They can perform tests such as colonoscopy and diagnose conditions like IBS, IBD and coeliac disease. For any emergency signs, such as severe dehydration, fainting or heavy bleeding, call 995 or go to the nearest hospital.
Related guides
- Best Gastroenterology Clinics in Singapore — our editorial shortlist
- gastroenterology clinics directory
- Find a gastroenterologist
- Find a gastroenterologist
- Find a gastroenterologist
Sources
- HealthHub Singapore – Diarrhoea
- NHS – Diarrhoea and vomiting
- Mayo Clinic – Diarrhea
- SingHealth – Irritable Bowel Syndrome
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