Persistent Diarrhoea: Causes, Symptoms & Treatment

Why Am I Having Persistent Diarrhoea?

Most people experience diarrhoea from time to time, often following a viral illness, food poisoning or dietary indiscretion. However, when diarrhoea becomes persistent, recurrent or difficult to explain, it may indicate an underlying digestive issue that warrants further assessment.

Persistent diarrhoea can occur in isolation or alongside symptoms such as bloating, abdominal discomfort, urgency, excess gas or food reactivity. In some cases, it may be related to Irritable Bowel Syndrome (IBS), Small Intestinal Bacterial Overgrowth (SIBO), food intolerances or other gastrointestinal conditions.

Identifying the contributing factors is often the first step towards improving symptoms and supporting long-term digestive health.

What Is Diarrhoea?

Diarrhoea refers to bowel motions that are loose, watery or more frequent than is normal for an individual.

For some people, symptoms are short-lived and resolve without intervention. For others, chronic diarrhoea or persistent loose stools may continue for weeks or months, fluctuate with periods of constipation or become a recurring problem that affects quality of life.

Diarrhoea may occur alongside:

  • Abdominal discomfort or cramping

  • Bloating

  • Excess gas

  • Urgency

  • Incomplete evacuation

  • Food reactivity

  • Fatigue

  • Unintentional weight loss

If diarrhoea is severe, persistent or accompanied by blood, fever, dehydration or significant weight loss, prompt medical assessment is recommended.

What Does Persistent Diarrhoea Look Like?

Persistent diarrhoea can present in different ways. Some people experience loose stools every day, while others have intermittent episodes that keep returning.

Symptoms may include:

  • Loose stools every day

  • Frequent bowel movements

  • Urgency

  • Diarrhoea after eating

  • Alternating diarrhoea and constipation

  • Ongoing bloating

  • Excessive gas

  • Abdominal discomfort

  • Food reactivity

Looking at the overall symptom pattern can help identify whether further investigation may be appropriate.

Common Causes of Persistent Diarrhoea

Persistent diarrhoea can have many different causes, and the same symptom may arise from very different underlying mechanisms.

Potential contributors include:

  • Irritable Bowel Syndrome (IBS)

  • Small Intestinal Bacterial Overgrowth (SIBO)

  • Food intolerances

  • Coeliac disease

  • Inflammatory bowel disease

  • Gut infections

  • Bile acid malabsorption

  • Medication side effects

  • Hyperthyroidism

  • Pancreatic insufficiency

  • Microscopic colitis

In some cases, more than one factor may be contributing simultaneously, which is why a thorough assessment is important.

Diarrhoea After Eating

Some people notice that their symptoms occur shortly after meals.

Diarrhoea after eating may have a number of possible explanations, including an exaggerated gastrocolic reflex, food intolerances, bile acid malabsorption, IBS or excessive bacterial fermentation within the small intestine.

For others, symptoms may be triggered by high FODMAP foods, large meals, caffeine, alcohol or fatty foods.

Rather than eliminating increasing numbers of foods, it is often more helpful to understand why symptoms are occurring in the first place.

IBS and Diarrhoea

IBS with diarrhoea (IBS-D) is characterised by recurrent abdominal pain associated with altered bowel habits.

Although IBS is a recognised diagnosis, it is considered a syndrome rather than a single disease process. Two people with IBS may experience similar symptoms but have very different contributing factors.

Exploring diet, gut function, previous infections, stress, bowel patterns and other potential drivers may provide additional insight into persistent symptoms.

Could SIBO Cause Diarrhoea?

For some people, yes.

Hydrogen-dominant Small Intestinal Bacterial Overgrowth (SIBO) is commonly associated with:

  • Frequent loose stools

  • Urgency

  • Bloating after meals

  • Excess gas

  • Abdominal discomfort

Not everyone with diarrhoea has SIBO, and not everyone with SIBO experiences diarrhoea. However, where symptoms suggest excessive fermentation or persist despite conventional management, further investigation may be appropriate.

Can Food Intolerances Contribute?

Certain foods may trigger diarrhoea in susceptible individuals.

Common examples include:

  • High FODMAP foods

  • Lactose-containing foods

  • Excess fructose

  • Sugar alcohols

  • Large amounts of caffeine

  • Alcohol

  • Very high-fat meals

Food triggers vary significantly between individuals, and unnecessarily restrictive diets are generally not intended as a long-term solution.

Gut Health and Persistent Diarrhoea

Persistent diarrhoea may be a sign of underlying digestive dysfunction or altered gut health rather than simply an isolated symptom.

Factors such as impaired digestion, altered gut motility, changes in the gut microbiome, previous gastrointestinal infections and nervous system function can all influence bowel habits.

Considering these broader influences may provide additional insight into why symptoms developed and what support may be most appropriate.

When Should Ongoing Diarrhoea Be Investigated?

Further assessment may be appropriate if you experience:

  • Diarrhoea lasting longer than several weeks

  • Recurrent or unpredictable loose stools

  • Persistent bloating or excess gas

  • Food reactivity

  • Ongoing abdominal discomfort

  • Unexplained weight loss

  • Iron deficiency or other nutrient deficiencies

  • Symptoms that began after food poisoning or gastroenteritis

  • Symptoms that continue despite dietary changes

Depending on the clinical picture, investigation may include medical testing, pathology or functional testing where appropriate.

A Functional Approach to Persistent Diarrhoea

Rather than focusing solely on symptom suppression, it can be helpful to understand why diarrhoea developed in the first place.

Assessment may consider factors such as:

  • Digestive function

  • Gut motility

  • Bacterial fermentation

  • Previous gastrointestinal infections

  • Diet and eating patterns

  • Stress and nervous system health

  • Gut barrier function

  • Nutrient status

  • Lifestyle factors

Because diarrhoea can have multiple contributing factors, treatment is often most effective when tailored to the individual rather than following a standard protocol.

You may also find it helpful to learn more about IBS, SIBO, bloating, constipation, and reflux as these conditions and strategies commonly overlap with persistent digestive symptoms.

Book a Consultation

If you're experiencing persistent diarrhoea, recurrent loose stools, bloating or ongoing digestive symptoms, a comprehensive assessment can help identify the factors contributing to your presentation and determine whether further investigation or individualised support may be appropriate.

Consultations are available in Maroochydore, Forest Glen and via Telehealth across Australia.