IBS and Explosive Diarrhoea: What to Do in an Emergency

When your gut goes into overdrive: understanding what's happening

An overwhelming urge, cramps that strike without warning, a frantic dash to the nearest toilet… If you live with diarrhoea-predominant irritable bowel syndrome (IBS-D), these episodes are, unfortunately, far from uncommon. IBS affects between 4 and 11% of the global population, and its diarrhoeal form is one of the most disruptive to daily life.

But what is actually happening in your gut during one of these episodes? Several mechanisms may be at play:

• Accelerated colonic motility, which reduces the time available for water reabsorption, resulting in loose or liquid stools
• Hypersensitivity of the intestinal nerves, which amplifies the perception of pain and urgency
• The osmotic effect of certain FODMAPs (fermentable sugars), which draw water into the gut and produce gas as the microbiome ferments them
• In some individuals, bile acid malabsorption — often underdiagnosed — which can mimic or worsen urgent diarrhoea
• Stress, which disrupts the gut-brain axis and can trigger or intensify an episode

Understanding these mechanisms is already half the battle when it comes to building your emergency strategy.

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Priority number one: rehydration

During a diarrhoeal episode, your body loses both water and electrolytes (sodium, potassium, and so on). Overlooking this step is the most common mistake people make.

What to do:

• Drink little and often throughout the day, without waiting until you feel thirsty
• Aim for roughly 1.5 to 2.5 litres depending on the severity of the episode, adjusting according to your losses
• Good options include: still water, salted broths, caffeine-free herbal teas, light soups, and oral rehydration solutions
• Avoid mineral waters high in magnesium, as these can have an additional laxative effect in some people

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What you eat makes all the difference

During an acute episode, the goal is not to eat "healthily" in the conventional sense — it is to give your gut a rest while it settles down.

Foods to favour temporarily

• White and refined starchy foods: white rice, white pasta, white bread, semolina, instant oat flakes — easy to digest and low in fermentable residue
• Gentle fruits: ripe bananas, unsweetened apple purée, peeled or cooked fruit
• Cooked and peeled vegetables: carrots, courgettes, potatoes — soothing and low in irritants
• Small, frequent meals rather than large ones, to avoid overloading an already fragile gut

Foods to avoid during the episode

• Fatty foods: fried food, fatty cured meats, pastries, rich sauces — these speed up intestinal motility
• Insoluble fibre: wheat bran, wholegrain cereals, pulses, nuts, seeds, raw vegetables — these accelerate transit
• Stimulants and irritants: coffee, strong tea, alcohol, fizzy drinks
• Polyols such as sorbitol (found in some sweets, chewing gum, and stone fruits)
• Dairy products high in lactose, if your tolerance is poor

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After the episode: getting back on track gradually

Once an episode has passed, it can be tempting to jump straight back to your normal diet. Take the time to reintroduce higher-fibre foods and raw vegetables gradually, over the course of several days.

In the medium term, the best-evidenced dietary approach for IBS remains the low-FODMAP diet, ideally followed with the support of a specialist dietitian. This is not a permanent exclusion diet, but rather a structured method for identifying your personal triggers.

Keeping a food and symptom diary is also an invaluable tool: note what you eat, your stress levels, the quality of your sleep, and your symptoms. Patterns often reveal unexpected triggers.

Finally, make a point of eating slowly and at regular times: irregular meals or eating too quickly can activate the gut-brain axis and make episodes more likely.

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⚠️ When to seek medical advice without delay

Diarrhoea in IBS is debilitating, but it is functional in nature. Certain warning signs should prompt you to see a doctor promptly, as they may indicate a more serious underlying cause:

• Blood in your stools
• Fever
• Unexplained weight loss
• Nocturnal diarrhoea (waking you from sleep)
• Severe or persistent pain
• Signs of serious dehydration (dizziness, very dry mouth, little or no urine output)
• A lasting, unexplained change in bowel habit

These symptoms fall outside the typical picture of IBS and warrant a thorough medical assessment.

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Key takeaways

Explosive diarrhoea in IBS is exhausting, but there are concrete strategies that can help you regain control. Rehydration first, simple and frequent meals, and temporary avoidance of known triggers: these are the cornerstones of effective crisis management. And in the longer term, identifying your personal triggers — with professional support if needed — remains the best way to reduce both the frequency and severity of these episodes.