Most episodes of diarrhoea improve within a few days and are often caused by a short-term infection, food poisoning, or food-related illness. However, when diarrhoea lasts for several weeks or keeps coming back, it may be a sign of an underlying condition rather than a simple stomach upset.
Persistent or recurring diarrhoea can have many treatable causes, including lingering infections, food intolerances, irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), medication side effects, or problems with nutrient absorption.
Ongoing symptoms should not be ignored. Medical assessment can help identify the underlying cause, guide appropriate treatment, and reduce the risk of complications such as dehydration, weight loss, or poor nutrient absorption.
Diarrhoea is usually classified according to how long it lasts.
Acute diarrhoea usually lasts for less than two weeks and often improves within a few days. It is commonly caused by viral infections, food poisoning, or a short-term stomach infection.
Persistent diarrhoea lasts for two to four weeks.
Chronic diarrhoea lasts for more than four weeks or keeps recurring over time.
The longer diarrhoea continues, the more important it is to look for an underlying cause. Persistent or chronic diarrhoea should be assessed by a doctor, especially if symptoms are worsening, recurring, or associated with warning signs.
Diarrhoea may continue for longer than expected when the digestive system remains irritated, inflamed, infected, or unable to absorb certain nutrients properly.
Possible reasons include:
An infection that has not fully cleared
A parasite such as Giardia or Cyclospora
Post-infectious bowel irritation after food poisoning or gastroenteritis
Food intolerance or malabsorption
Irritable bowel syndrome
Inflammatory bowel disease
Medication side effects
Other underlying digestive or medical conditions
Identifying the cause is important because treatment depends on why the diarrhoea is continuing.
Most food poisoning improves within a few days. However, some infections can cause diarrhoea that lasts longer, especially if the infection is caused by certain bacteria or parasites.
In some people, diarrhoea may also continue after the original infection has cleared. This is known as post-infectious diarrhoea or post-infectious IBS, where the bowel remains sensitive for a period of time after gastroenteritis.
If diarrhoea lasts more than one to two weeks, worsens, or occurs with fever, blood in the stool, dehydration, or weight loss, medical assessment is recommended.
Persistent or recurring diarrhoea can result from a wide range of conditions. These causes can be grouped into several main categories.
Although many infections resolve on their own, some can cause diarrhoea that lasts for weeks. Possible causes include:
Bacterial infections
Parasitic infections such as Giardia
Cyclospora infection
Ongoing gut infection after contaminated food or water exposure
Post-infectious diarrhoea after the original infection has cleared
Travel history, food exposure, recent illness, and contact with others who are unwell may help guide the diagnosis.
Several digestive conditions can cause ongoing or recurring diarrhoea. These include:
Irritable bowel syndrome (IBS): IBS can cause recurring diarrhoea, abdominal cramps, bloating, and changes in bowel habits. Symptoms may come and go over time.
Inflammatory bowel disease (IBD): IBD includes Crohn’s disease and ulcerative colitis. These conditions cause chronic inflammation in the digestive tract and may lead to diarrhoea, abdominal pain, blood in the stool, fatigue, and weight loss.
Coeliac disease: Coeliac disease is an immune reaction to gluten that damages the small intestine. It can affect nutrient absorption and cause diarrhoea, bloating, weight loss, anaemia, or fatigue.
Some people develop diarrhoea because the body has difficulty digesting or absorbing certain foods. Common examples include:
Lactose intolerance
Fructose malabsorption
Sensitivity to certain artificial sweeteners
Fat malabsorption
Bile acid diarrhoea
Symptoms may worsen after certain meals and improve when specific triggers are identified and managed.
Certain medications can cause persistent or recurring diarrhoea as a side effect. These include:
Antibiotics
Some diabetes medications
Laxatives
Magnesium-containing supplements or antacids
Certain heartburn medications
Some anti-inflammatory medications
Do not stop prescribed medication without speaking to your doctor. If diarrhoea begins after starting a new medication, your doctor can advise whether adjustments are needed.
Less commonly, persistent diarrhoea may be linked to other medical conditions, including:
Hormonal disorders
Pancreatic disease
Gallbladder or bile acid-related problems
Colorectal cancer
Colorectal cancer is not a common cause of diarrhoea, but it should be considered when diarrhoea is accompanied by warning signs such as blood in the stool, unexplained weight loss, persistent abdominal pain, iron deficiency anaemia, or a significant change in bowel habits.
Many cases of diarrhoea improve with time, but persistent or recurring symptoms should be assessed if they do not resolve or keep returning.
Seek medical advice promptly if you experience:
Diarrhoea lasting more than one to two weeks
Blood in the stool
Black stools
Unexplained weight loss
Severe or persistent abdominal pain
Fever or signs of infection
Dizziness, extreme thirst, reduced urination, or other signs of dehydration
Diarrhoea that wakes you from sleep at night
Persistent vomiting
A new or unusual change in bowel habits, especially in older adults
Diarrhoea with known inflammatory bowel disease or a weakened immune system
These warning signs may suggest infection, inflammation, bleeding, dehydration, or another condition that requires medical attention.
Persistent diarrhoea should be treated as urgent if there are signs of severe dehydration, severe infection, or significant bleeding.
Seek urgent medical care if you experience:
Fainting or severe dizziness
Very little or no urination
Confusion or extreme weakness
Severe abdominal pain
High fever
Bloody diarrhoea
Black stools
Rapid worsening of symptoms
Children, older adults, pregnant women, and people with weakened immune systems may become dehydrated more quickly and should seek medical advice earlier.
Diagnosis usually begins with a review of your symptoms, medical history, diet, medications, recent infections, and travel history. Your doctor will also ask about the frequency, timing, appearance, and pattern of your bowel movements.
A physical examination may be performed to check for dehydration, abdominal tenderness, weight loss, or other signs that may point to the underlying cause.
Depending on your symptoms and risk factors, tests may include:
Stool tests to check for infections, parasites, inflammation, blood, or other abnormalities.
Blood tests may help assess infection, inflammation, anaemia, nutritional deficiencies, thyroid function, coeliac disease, or other medical conditions.
Imaging tests like ultrasound, CT scan, or other imaging tests may be recommended when doctors need to evaluate the digestive tract or surrounding organs.
Endoscopic procedures such as a colonoscopy or other endoscopic test may be recommended to examine the lining of the digestive tract and obtain tissue samples if needed.
Identifying the underlying cause is essential for determining the most appropriate treatment.
Treatment depends on the cause of the diarrhoea. Once the underlying diagnosis is identified, your doctor will recommend a treatment plan tailored to your condition.
Treatment may include:
Replacing fluids and electrolytes
Treating infections with appropriate medication where needed
Adjusting medications if diarrhoea is a side effect
Managing food intolerances through dietary changes
Treating inflammatory bowel disease or other digestive disorders
Correcting nutritional deficiencies
Managing dehydration or complications
Although some medications may help relieve symptoms, persistent or recurring diarrhoea should not be managed with over-the-counter remedies alone. Treating the underlying cause is important for long-term recovery.
When diarrhoea continues, hydration is the first priority. Drink small, frequent amounts of fluid and consider oral rehydration solutions if there are signs of dehydration.
Food choices may depend on the cause of diarrhoea, but during active symptoms, some people may tolerate simple foods better, such as:
Rice
Bananas
Toast
Plain porridge
Crackers
Soup or broth
Boiled potatoes
Avoid alcohol, very oily foods, and foods that clearly worsen symptoms. If diarrhoea is linked to lactose intolerance, coeliac disease, or another condition, your doctor or dietitian may recommend a more specific dietary plan.
Prevention depends on the underlying cause. Not every case of persistent or chronic diarrhoea can be prevented, but some measures may reduce the risk. These include:
Practising good hand hygiene
Handling and storing food safely
Drinking safe, clean water when travelling
Identifying and managing trigger foods
Taking medications only as directed
Discussing persistent side effects with your doctor
Maintaining a balanced diet to support digestive health
Seeking medical advice early when diarrhoea persists or keeps recurring
Early diagnosis and appropriate treatment remain the best approach when symptoms do not improve.
If you are experiencing persistent or recurring diarrhoea, do not ignore ongoing symptoms, especially if they are associated with blood in the stool, unexplained weight loss, abdominal pain, fever, dehydration, or diarrhoea that wakes you at night.
At Prince Court Medical Centre, our gastroenterologists provide comprehensive evaluation for persistent diarrhoea, chronic diarrhoea, recurring bowel symptoms, food intolerances, inflammatory bowel disease, infections, and other digestive conditions.
Our team can recommend appropriate tests and develop a personalised treatment plan based on your symptoms, diagnosis, and overall health. Book an appointment with us today for further assessment and personalised care.
Reviewed by Dr Ahmad Najib Azmi
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