Irritable bowel syndrome (IBS) | Mate tikotiko

Key points about irritable bowel syndrome

  • IBS is a chronic (ongoing) gastrointestinal (gut) condition. IBS is not the same as inflammatory bowel disease (IBD).
  • IBS can be uncomfortable but is usually harmless. 
  • Symptoms include bouts of abdominal (tummy) discomfort and pain, bloating and changeable bowel habits from diarrhoea (runny poo) to constipation (hard poo).
  • IBS affects 1 in 7 people and is more common in women than men, and in those aged under 50.
  • There are simple first line dietary and lifestyle changes that can help improve your symptoms.
  • If your symptoms are ongoing talk to your healthcare provider about medicines to help relieve specific symptoms.
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Video: What is irritable bowel syndrome?

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(NHS, UK, 2022)

The exact cause of IBS is still not certain. However, there is emerging evidence that changes in your gut bacteria and inflammation of your immune system may play a role in its development.

In particular, factors that contribute to IBS are thought to be:

  • sensitivity – you may have a more sensitive gut (sometimes called ‘visceral sensitivity’)
  • digestion speed – the contents of your gut may move unusually quickly or slowly (sometimes called ‘altered gut motility’)
  • bacteria – you may have an imbalance of ‘good’ and ‘bad’ bacteria in your gut (sometimes called ‘dysbiosis’)
  • leaky gut – your gut may be slightly inflamed or ‘leaky’, eg, it may have small cracks or openings that allow partially digested food, toxins and bugs to get through the gut barrier
  • infection – you may have had an infection, such as gastroenteritis, that trigged the IBS. 

The most common symptoms of IBS are abdominal pain or discomfort, often reported as cramping, along with changes in bowel habits. 

Usually the pain or discomfort will be associated with at least 2 of the following 3 symptoms:

  • Feeling better after having a bowel movement.
  • Having bowel movements more or less often than usual.
  • Having diarrhoea or constipation as defined below:
    • diarrhoea – having loose, watery stools (poo) 3 or more times a day and feeling urgency to have a bowel movement
    • constipation – having fewer than 3 bowel movements a week. Stools can be hard, dry and small, making them difficult to pass. Some people find it painful and often have to strain to have a bowel movement.

For a diagnosis of IBS, these symptoms must occur at least 3 times a month.

Other symptoms of IBS may include:

  • feeling that a bowel movement is not completely finished
  • passing mucus – a clear liquid made by your gut that coats and protects its tissues
  • urinary incontinence (not able to control your bladder)
  • faecal incontinence (not able to control your bowel)
  • feeling bloated.

IBS can be triggered by diet and lifestyle, especially stress and anxiety. 

Most people with IBS notice that food triggers symptoms. Common trigger foods include:

  • dairy
  • fatty foods
  • spicy foods
  • fizzy drinks
  • caffeine
  • artificial sweeteners. 

Additionally, a group of short-chain carbohydrates called FODMAPs(external link) (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) are also known to trigger symptoms in some people.

If you have the symptoms above, see your healthcare provider for a check-up. See them immediately if have any of the following symptoms: 

Your healthcare provider will usually make a diagnosis based on your symptoms. Because the symptoms of IBS are similar to those of more serious conditions, you may have one or more of the following tests:

There is no cure for IBS, but there are treatments that can make a big difference. Talk to your healthcare provider about what might be best for you. 

The following approaches help a lot of people to manage their symptoms.

Keep a food, mood and symptom diary

Keep a diary of your symptoms and what you have changed (food or lifestyle). It will help you to see when you are feeling better and when you are feeling worse. Take note of how you felt as well, as feelings like stress and anxiety can affect your symptoms.

Eat mindfully and regularly

  • The gut loves regularity so eating meals at regular times throughout the day (and not skipping meals!) will help your digestion. This may mean 3 main meals or 3 smaller meals with snacks in between. Intermittent fasting is not useful for people with IBS as skipping meals can slow down your digestion.
  • Make sure you chew your food and eat slowly to support your digestion.
  • Eat to your level of hunger. Often we eat out of habit, so before eating, ask yourself how hungry you are. If you’re not very hungry, have a smaller meal or snack. Stop eating when you are full or comfortable. This will also help you eat more regular meals.

Choose nourishing foods

Eat a variety of foods from the 4 food groups. Learn more about the 4 food groups and healthy eating. 

Food swaps for specific symptoms

Certain foods are known to make symptoms worse.

For diarrhoea:

  • Replace fluids by drinking 8-10 cups of water per day.
  • Limit aggravating foods such as fatty foods, spicy foods, caffeine and alcohol.
  • Have a break from artificial sweeteners, usually found in chewing gums and sugar free drinks.
  • Slightly reduce insoluble fibre intake and slowly eat more soluble fibre. Learn more about fibre(external link).
  • Trial a dairy free diet for two weeks. Try lactose free milk, soy, oat or almond milk. Hard cheeses like Edam and tasty have no lactose, so you can still eat these. After two weeks, if it makes no difference, re-introduce dairy back in.

For constipation:

  • Try to slowly increase your fibre intake with whole gains, fruits, vegetables, legumes, nuts & seeds. Learn more about fibre(external link).
  • Try green kiwifruit (1-2 per day) or prunes (1-4 per day).
  • Drink at least 8 glasses of fluid each day
  • Try whole or ground linseed: start with 1 teaspoon per day and increase every few days to a maximum of 3 teaspoons. Make sure you have 50mls of fluid with each teaspoon of ground linseed.
  • Try Psyllium husk, which is available on prescription from your healthcare provider. Start slow increasing from 10g to 30g over 2–4 doses throughout the day, trial for 3 months.

For reflux/indigestion:

  • Eat small, frequent meals.
  • Sit upright after eating; reclining or lying down will make reflux worse. Avoid eating within 1–2 hours of sleep.
  • Avoid fizzy drinks, alcohol and caffeine.
  • Reduce spicy foods and fatty foods.

Drink plenty – but choose wisely

  • Try to have at least 8 cups (250ml) of water a day.
  • Caffeine can irritate your gut. Try not to have more than 3 caffeine drinks (tea, coffee, cola) each day. Reducing your coffee intake may improve your symptoms.
  • Fizzy drinks may make bloating or reflux worse. Try not to have fizzy drinks.
  • Alcohol irritates and speeds up the gut, so try a period of reduced alcohol.

Managing stress

Researchers have also found that reducing your stress can help to ease your symptoms. Read more about stress and how to manage it. 

Physical activity

There is evidence that being more active can help reduce your IBS symptoms. This may be because it helps digested food move through your gut, reducing gas and bloating. Read more about the benefits of physical activity.  

Cognitive Behavioural Therapy (CBT)

Because of the connection between the brain and the gut (the gut-brain axis), talking therapy such as CBT, has been found to be helpful in managing IBS symptoms.

Gut Directed Hypnotherapy

There is strong evidence to suggest that gut-directed hypnotherapy improves symptoms in people with IBS by 70-80%, which is as equally effective as the low FODMAP diet and there are no restrictive diets to follow. There are clinics that offer this in person, however a lower cost option are apps such as Nerva(external link), a 6 week programme developed by a gastroenterologist at Monash University.

Probiotics are live, beneficial bacteria found in fermented foods like yoghurt, kefir and tempeh or in pill form. The evidence to support the use of probiotics in IBS is inconclusive, there is some evidence behind certain strains so it’s best to speak to a dietitian. 

Probiotics may be beneficial for some people, but in others they may increase wind and bloating. 

If you want to trial a probiotic, it’s recommended you start slowly and try for a minimum of 4 weeks. If you don’t notice a change, or have an increase in your symptoms, stop taking them.

If you have tried all of the above tips and your symptoms don’t improve, it is recommended that you see a dietitian to follow a short-term low-FODMAP diet followed by a reintroduction phase.

Research suggests that 3 in 4 people with IBS get symptom relief, usually within 1–4 weeks, from following a low-FODMAP diet. These positive effects can continue long term. It’s best if you can see a dietitian experienced in this diet to help support you make the changes needed. 

FODMAPs are either poorly absorbed in your small intestine or are not digestible.

Because they are poorly absorbed, they reach the end of your digestive system (the large intestine or colon), where most of your gut bacteria live. Here, your gut bacteria ferment them, producing gas. This leads to bloating and flatulence.  

FODMAPS also have an osmotic effect, which means they draw water into your colon (bowel). This can cause cramping and more bloating. 

Depending on your digestive system, the combination of producing gas and drawing water in can lead to inconsistent or excessive bowel movements, diarrhoea or constipation, and tummy pain.

This process is likely to be made worse by stress and lack of physical activity. 

Read more about common foods containing FODMAPs(external link). There is also an app developed by Monash University to help you follow this diet. It is important that after a period of 4–6 weeks of a low FODMAP diet you start to reintroduce foods that contain FODMAPs so that you don’t have a lifetime of restricted eating and can enjoy a variety of foods. 

It is strongly recommended that you get support from a dietitian throughout this process, as it is important to follow the diet correctly and to ensure you are still getting a balanced diet.

Video: Monash University FODMAP Diet App Tour

The following video provides a tour of the Monash University FODMAP diet app. This video may take a few moments to load.

(Monash University, 2022)

Many dietitians and doctors now recommend a low-FODMAP diet as a key part of a treatment plan for people with IBS. 

Most people with IBS who have tried the diet have experienced a great improvement in their symptoms and a reduced need for medication. 

What are FODMAPs?  

Some foods can cause your bowel to stretch and expand. This usually happens because they contain elements that:

  • are 'osmotic' and draw in fluid
  • produce gas when they are fermented by bacteria in your bowel.

FODMAPs are the most common food element this happens with. They are fermentable, poorly absorbed, short-chain carbohydrates or 'sugars'.  They can't be digested by your body but are easily fermented by bacteria once they reach your bowel.

FODMAPs stands for:

  • Fermentable – rapidly broken down (fermented) by bacteria in your the bowel
  • Oligosaccharides – fructans and galacto-oligosaccharides (GOS)
  • Disaccharides – lactose
  • Monosaccharides – fructose
  • And
  • Polyols – sorbitol, mannitol, xylitol and maltitol.

If this seems too complex – just remember that 'saccharide' is a different word for sugar. Polyols are sugar alcohols — meaning sugar molecules that have an alcohol side-chain attached. You might already know some of these sugars or have seen them in ingredients lists on food packaging.

What are some common foods containing FODMAPs? 

Common FODMAPs include:

  • fructose in fruits such as apples, pears and mango, and in honey and high fructose corn syrup
  • concentrated sources of fructose, e.g., dried fruit, tomato paste and wine
  • fructans in wheat, rye, onions, spring onions, leek, asparagus and artichokes
  • artificial sweeteners such as sorbitol, xylitol, mannitol (found in products such as sugar-free chewing gum, sweets and drinks). 

*This table is not an exhaustive list of high and low FODMAP foods. For a comprehensive database of FODMAP food information, see the Monash University FODMAP Diet App or High and low-FODMAP foods(external link), Monash University, Australia.

A low-FODMAP diet is not for life 

The goal of a low-FODMAP diet is usually to remove the problem foods and then slowly reintroduce them over time. Carry out any changes to your diet with help from your doctor or a dietitian. 

You don't need to cut out all FODMAPs for life. Removing food groups from your diet can result in nutrient deficiencies.

Source: Starting the low-FODMAP diet(external link) Monash University, Australia

Vdieo: Three Phases of the Low FODMAP Diet Chat Session

Watch a video about the 3 phases of the FODMAP diet and some helpful tips. This video may take a few moments to load.

(A Little Bit Yummy, 2023)

More videos about FODMAP and IBS can be found on the A Little Bit Yummy YouTube channel(external link)

Learn more 

Low FODMAP smartphone app(external link) Monash University, Australia, 2015
Starting the low-FODMAP diet(external link) Monash University, Australia
A little Bit Yummy(external link) YouTube channel 
A Little Bit Yummy(external link) FODMAP made easy  (paid membership)

There are medicines that can help with some symptoms of IBS such as pain, constipation or diarrhoea. Medicines can help to control the severity of the symptoms but do not reverse or “cure” them.

Each person with IBS will have different symptoms and medicines are aimed at easing your most troublesome symptom or combination of symptoms. 

Ask your doctor or nurse for dietary advice; many people with IBS find that certain foods such as FODMAPS can trigger symptoms and following a low-FODMAP diet can be beneficial.

Abdominal pain and bloating medicines


Medicines that relax the stomach (tummy) muscles can be used to used to relieve tummy cramps or spasm-type pain that can occur with IBS. They can also help to ease bloating. These medicines are called anti-spasmodics.

Examples of anti-spasmodics include hyoscine tablets (Buscopan® or Buscopan Forte®) and mebeverine (Colofac®).

Your doctor may recommend a 1 week trial of taking these regularly. If they work, then you may be advised to use them as required, when the symptoms arise. Read more about hyoscine tablets and mebeverine.

Peppermint oil

There is some evidence that peppermint oil may be useful for bloating, wind and bowel cramps. However, in some people, peppermint oil can cause or worsen reflux (indigestion).

In New Zealand, peppermint oil is available as capsules (Mintec® and Colpermin®). 

Your doctor may recommend a trial of 1 capsule 3 times daily 30–60 minutes before meals for 2 weeks. If it's helpful, you can continue taking these, but reduce to the lowest effective dose. Ask your pharmacist for advice on how to take peppermint oil capsules. 

Constipation medicines

If your main symptom is constipation, laxatives may help. There are a variety of different laxatives which work in different ways. Some laxatives can cause bloating, flatulence and discomfort, which can make your IBS worse. Your doctor or pharmacist can advise you on the best laxative for you. You may need to try a few laxatives before you find the right one for you. Read more about laxatives.

Diarrhoea medicines

If diarrhoea (runny poos) is your main problem, medicines such as loperamide may be helpful to increase stool firmness, decrease stool frequency and reduce urgency. This can be used in combination with an anti-spasmodic such as mebeverine.

Loperamide works by slowing the movement of the gut, and in this way reduces the number of bowel motions and firms up runny poos.

Your doctor will start you on a low dose and depending on your symptoms, may increase your dose gradually. Do not take more than 8 tablets in 24 hours.

An approach that has been suggested for people who are fearful of the sudden and urgent need to defaecate (poo) that can occur with IBS, is for them to take 2–4 mg of loperamide approximately 45 minutes before leaving their house, particularly if access to a toilet is limited, such as when shopping or exercising.

Note that additional doses need to be carefully managed to avoid constipation later in the day. Discuss the best options with your doctor or pharmacist. 

Another medicine that may be used for diarrhoea associated with IBS is mebeverine. Read more about loperamide and mebeverine

Other medicines


Some people may be started on a trial of antidepressants such as amitriptyline or nortriptyline. These are used to relieve pain and slow movement of the gut, rather than treatment of psychological symptoms.

You will be started on a low dose and if needed, your dose will be increased only after 3 to 4 weeks. Amitriptyline or nortriptyline may not be suitable if you also have constipation. Read more about amitriptyline and nortriptyline


The evidence to support the use of probiotics in irritable bowel syndrome is inconclusive (not clearly for or against their use). A 4-week trial of probiotics in the form of yoghurts or other fermented milk products can be considered. However, some of these products also contain ingredients that may worsen IBS symptoms, such as fructans, fructose or lactose. Read more about probiotics

IBS Central(external link) Monash University, Australia
IBS resources(external link) Monash University, Australia
A Little Bit Yummy(external link) FODMAP made easy (paid membership)


Strategies for managing IBS - FODMAP and beyond(external link) A Little Bit Yummy, NZ
Three phases of the low FODMAP diet chat session(external link) A Little Bit Yummy, NZ
FODMAP Stacking - FODMAP Chat Session with Monash University(external link) A Little Bit Yummy, NZ

More videos can be seen on the A Little Bit Yummy(external link) site. 


Trouble going to the loo? [PDF, 1.1 MB] Healthify He Puna Waiora, NZ
Common foods containing FODMAPs(external link) Health Food Media, NZ
Monash University low FODMAP diet guide(external link) Monash University, Australia
Further investigation – colonoscopy results(external link) Health Ed, NZ


  1. Irritable bowel syndrome in adults – not just a gut feeling(external link) BPAC, NZ, 2014
  2. Irritable bowel syndrome(external link) Crohn’s & Colitis, NZ
  3. Low FODMAP diet efficacy in IBS patients – what is the evidence and what else do we need to know?(external link) NZ Medical Journal, 2016
  4. Johannesson E, Ringström G, Abrahamsson H, Sadik R. Intervention to increase physical activity in irritable bowel syndrome shows long-term positive effects(external link) World J Gastroenterol. 2015;21(2):600–608.
  5. Qin H-Y, Cheng C-W, Dong Tang X-D, Bian Z-X. impact of psychological stress on irritable bowel syndrome (external link)World J Gastroenterol. 2014;20(39):14126–14131.
  6. Kinsinger SW. Cognitive-behavioral therapy for patients with irritable bowel syndrome: current insights(external link) Psychol Res Behav Manag. 2017;10:231–237.
  7. How effective is gut-directed hypnotherapy in people with IBS?(external link) Monash University, Australia

Clinical pathways and guidelines

Telehealth clinical module – abdominal assessment(external link) ProCare, NZ, 2022

Low FODMAP diet resources

Continuing professional development

Simplifying IBS – targeted management that isn’t just FODMAPS(external link) (Goodfellow Unit Webinar, NZ, 2020)
Irritable bowel syndrome by Dr Adele Melton(external link) (The Goodfellow Unit, NZ, 2018)
Functional GI disorders – Dr Anne Tait (29 minutes)(external link) (PHARMAC, NZ, 2020)
Treating IBS(external link) Monash University, Australia
Irritable bowel syndrome – new and emerging treatments(external link)  BMJ Learning, 2015
Wilson H, et al. Te Kete – diagnosis and explanations for patients with 'persistent somatic symptoms' and chronic pain [PDF, 2 MB] NZ, 2024


common foods containing fodmaps

Common foods contaning FODMAPs

Health Food Media, NZ

monash university low fodmap guide

Monash University low FODMAP diet guide

Monash University, Australia

Trouble going to the loo?

Healthify He Puna Waiora and Mediboard, 2023

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Credits: Healthify editorial team. Healthify is brought to you by Health Navigator Charitable Trust.

Reviewed by: Dr Derek JY Luo, MBChB (Otago) FRACP, Consultant Gastroenterologist; Gabrielle Orr & Amanda Buhaets, NZ Registered Dietitians, Auckland

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