Acute diarrhoea is a very common condition affecting both adults and children. It usually begins suddenly and presents with loose or watery stools occurring several times a day. It may also be accompanied by abdominal cramps, fever, nausea or vomiting.
In most cases, acute diarrhoea is caused by a gastrointestinal infection. Viruses are the most frequent culprits, although bacteria and parasites can occasionally be responsible. Non-infective causes such as medication side effects, hormonal conditions and acute gastrointestinal diseases can also trigger sudden diarrhoea.
Acute diarrhoea is usually self-limiting, meaning it resolves on its own or with simple home treatment. However, if symptoms last longer than two weeks, the condition is no longer considered “acute”. Persistent or chronic diarrhoea may indicate underlying conditions such as inflammatory bowel disease, irritable bowel syndrome, pancreatic disorders or food intolerances. Symptoms such as weight loss, ongoing abdominal pain or fever warrant medical evaluation.
Common Causes of Acute Diarrhoea
1. Viral Gastroenteritis (Most Common Cause)
Viruses cause the majority of acute infections. Symptoms are typically mild and stools are watery rather than bloody.
Common viral causes include:
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Rotavirus (more common in children)
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Norovirus (common in adults and outbreaks)
These viruses spread through the faecal–oral route, often through contaminated hands, food or drinks. To reduce risk:
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Wash hands thoroughly with soap and water (sanitisers may not kill certain viruses).
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Avoid raw or undercooked foods, especially while travelling.
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Be cautious with ice, fruit juices and drinks in places with poor hygiene standards.
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Choose bottled water from reliable sources.
2. Bacterial and Parasitic Infections
Bloody diarrhoea is more concerning and often indicates inflammation of the bowel. This can be caused by bacteria such as:
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Salmonella
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Shigella
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Campylobacter
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Escherichia coli (certain strains)
Parasites like Amoeba or Giardia can also lead to prolonged or severe diarrhoea. These infections are more common among hikers or travellers who drink untreated river or lake water.
How to Treat Acute Diarrhoea at Home
Most cases can be managed safely with simple measures:
1. Rehydration (Most Important Step)
Diarrhoea leads to loss of water and electrolytes. Replacing these is essential.
The best option is Oral Rehydration Solution (ORS), available at pharmacies.
If unavailable, you may use:
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Sports drinks
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Diluted fruit juices
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Clear soups
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Salted crackers (to replace sodium)
Small, frequent sips help prevent vomiting.
2. Continue Eating
Early feeding helps the gut recover faster. Choose light, easy-to-digest meals such as:
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Porridge or rice
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Noodles
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Bananas
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Toast
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Boiled vegetables
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Clear broths
Avoid heavy, oily, spicy or dairy-rich foods while recovering.
3. Medications for Symptom Relief
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Loperamide reduces stool frequency by slowing gut movement.
It works even better when combined with simethicone for gas relief. -
Adsorbents like Smecta or activated charcoal may help bind toxins.
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Probiotics are beneficial and may shorten the duration of symptoms.
Avoid loperamide if you have bloody stools, high fever, or suspicion of bacterial infection — it may worsen the condition.
4. When Are Antibiotics Needed?
Most adults with mild, watery diarrhoea do not need antibiotics.
A doctor may prescribe them only if:
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Diarrhoea is severe
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Stools are bloody
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There are signs of dehydration
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There is high fever
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A bacterial infection is strongly suspected
Unnecessary antibiotics can worsen diarrhoea and cause resistance.
When to Seek Medical Attention
See a doctor early if:
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The patient is a young child, older adults, or someone with chronic illnesses
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There are signs of dehydration (dry mouth, dizziness, very little urine)
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Symptoms worsen or last longer than 48–72 hours
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Stools are bloody
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There is persistent vomiting
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There is ongoing fever
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The diarrhoea lasts more than two weeks
Some patients may require hospitalisation for intravenous fluids or further investigations such as stool tests. In rare cases, a colonoscopy may be needed to rule out colitis or other serious bowel conditions.
