Irritable Bowel Syndrome (IBS)
Table of Contents
Irritable bowel syndrome, or IBS, is one of the most common digestive conditions seen in Australia, affecting around one in five people at some point in their lives. It causes real, often disruptive symptoms, but it is not a disease that damages the bowel, and with the right management plan, symptoms can be effectively controlled. Our gastroenterologists have considerable experience in diagnosing and treating IBS, helping patients in Brisbane and across Queensland get the clarity and relief they need.
What Is Irritable Bowel Syndrome?
IBS is a condition that affects the large bowel (colon), which is the part of the digestive tract responsible for storing and passing stool. People with IBS tend to have a bowel that is more sensitive and reactive than usual, a characteristic sometimes described as visceral hypersensitivity. This increased sensitivity can produce discomfort and abnormal contractions in the bowel muscle, even in the absence of any structural damage or abnormality on testing.
A useful way of understanding IBS is as a disorder of brain-gut interaction, a term that reflects how disruptions to the communication pathway between the brain and the gut can generate real physical symptoms. This is different from inflammatory bowel disease (IBD), which includes Crohn’s disease and ulcerative colitis. IBD involves active inflammation and tissue damage that can be detected on investigation. IBS does not.
IBS is more common in women than in men and often first presents in early adulthood. Symptoms tend to come and go over a person’s life rather than follow a steady course. It is worth knowing that IBS cannot be cured, but with appropriate management most people are able to control their symptoms effectively and maintain a good quality of life.
Symptoms of IBS
Core symptoms
The main symptoms of IBS centre on abdominal pain or discomfort, bloating, and a change in bowel habits involving diarrhoea, constipation, or a combination of both. Abdominal discomfort is often partially or fully relieved by passing wind or opening the bowels. Other symptoms may include mucus in the stool, a persistent feeling that the bowel has not fully emptied after a motion, abdominal distension, and nausea.
IBS subtypes
IBS is generally grouped according to the predominant bowel pattern. In constipation-predominant IBS, the person tends to alternate between constipation and normal stools. In diarrhoea-predominant IBS, loose or frequent stools are the main feature, and the urge to open the bowels can be sudden and difficult to defer. Incontinence may be a concern for some people with this subtype. The third pattern is an alternating mix of constipation and diarrhoea. Identifying your predominant pattern helps guide the most appropriate approach to management.
Symptoms in women
Women with IBS often notice that symptoms become more troublesome around the time of menstruation. This relates to the way fluctuating oestrogen and progesterone levels during the menstrual cycle influence gut receptors and bowel function.
Symptoms that require prompt medical attention
Some symptoms are not consistent with IBS and require prompt investigation to rule out a more serious condition. You should see your doctor without delay if you notice blood in your stools, unexplained weight loss, a fever, severe diarrhoea at night, or symptoms that are rapidly worsening or persistent. These features fall outside the typical picture of IBS and need to be assessed by a doctor.
What causes IBS?
The underlying cause of IBS is not fully understood, and the factors that contribute to it differ from person to person. It is important to note that stress does not cause IBS. However, strong emotions such as anxiety and stress can affect the nerves of the bowel in susceptible individuals and make existing symptoms significantly worse. For some people, significant emotional difficulties or past stressful life experiences may be a contributing factor worth exploring with appropriate support.
A number of other triggers are known to provoke symptoms in people with IBS. An episode of gastroenteritis or food poisoning is a common starting point, possibly because infection can alter nerve function in the bowel or disrupt the normal bacterial population of the gut. Food intolerances, particularly impaired absorption of certain carbohydrates including lactose, fructose, and sorbitol, are among the most frequent dietary triggers. A low-fibre diet can worsen constipation in those prone to it. Certain medications including antibiotics, antacids, and pain relief medicines are also known to trigger or aggravate symptoms, as are alcohol, caffeine, and smoking.
How is IBS diagnosed?
If your symptoms are typical of IBS and you are under 40 with no concerning features, your doctor may be able to make a diagnosis without extensive testing. However, further investigation is generally recommended if you are over 40 when symptoms first develop, if you have a family history of bowel cancer, or if there is any possibility that your symptoms are caused by another condition.
IBS is a diagnosis of exclusion, meaning other conditions need to be ruled out first. These may include infections, inflammatory bowel disease (IBD), coeliac disease, lactose intolerance, polyps, and bowel cancer. Investigations that may be arranged include blood tests (including testing for coeliac disease), stool tests, and endoscopic procedures such as colonoscopy or sigmoidoscopy. A diagnosis of IBS is generally supported when symptoms have been present for at least six months and investigations come back within normal limits.
A confirmed diagnosis is not simply a formality. It provides the foundation for a structured, evidence-based management plan and ensures that conditions requiring different treatment are not overlooked.
Treatment and management of IBS
An individualised approach
Because IBS is driven by individual triggers, management is tailored to each person rather than following a single formula. The goal is to identify what is contributing to your symptoms and put a plan in place that works for your life. Treatment is often only needed during flare-ups, and many people manage well with dietary and lifestyle changes alone. For others, a combination of dietary modification, medication, and other therapies provides the best outcome.
Diet and Nutrition
Dietary changes are often the most effective long-term strategy for managing IBS. Working with a dietitian helps you identify personal food triggers while keeping your overall diet nutritionally sound.
General dietary strategies that support symptom management include eating regular meals, avoiding sudden changes to eating patterns, increasing intake of high-fibre foods such as wholegrains, fruit, vegetables, and legumes, and staying well hydrated with water, teas, or juices throughout the day. If your diet is currently low in fibre, increasing it gradually is important, as introducing too much fibre too quickly can temporarily worsen bloating and discomfort. For most people, a daily fibre intake of around 30 grams is a reasonable target.
Foods and drinks commonly associated with worsening symptoms include gas-producing vegetables such as onion, cabbage, Brussels sprouts, dried beans, and lentils; foods containing lactose such as milk and ice cream; foods high in fructose or sorbitol; alcohol; caffeine; spicy foods; and high-fat or deep-fried foods. Artificial sweeteners, particularly those ending in ‘ol’ such as sorbitol and mannitol, are also worth reducing.
A more targeted dietary approach, where general changes are insufficient, is the low-FODMAP diet. FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides and polyols, which are types of carbohydrate poorly absorbed in the small intestine. When they reach the large intestine, they draw water into the gut and are fermented by bacteria, producing gas. This process can trigger bloating, pain, diarrhoea, and constipation in people with IBS. Common high-FODMAP foods include garlic, onion, apples, milk, mushrooms, wheat bread, and legumes such as chickpeas.
Research has shown that around three in four people with IBS experience meaningful symptom improvement on a low-FODMAP diet. The process involves an initial elimination phase of around two to six weeks, followed by a structured reintroduction phase to identify which specific foods are personal triggers. Long-term restriction of all high-FODMAP foods is not recommended, as many of these foods contain prebiotics that feed healthy gut bacteria and support the microbiome.
Dietitian guidance is strongly recommended for anyone undertaking the low-FODMAP process, as structured reintroduction and personalised advice are essential to doing it safely and effectively. You can find a dietitian by visiting the Dietitian Australia website.
Medications
A range of medications may be used to address specific IBS symptoms. These include anti-diarrhoeal medicines and fibre supplements for diarrhoea-predominant IBS, laxatives and fibre supplements for constipation-predominant IBS, and antispasmodic medicines for abdominal cramping. Peppermint oil capsules are a recognised antispasmodic option. Certain medications that act on pain signalling pathways can also be effective for managing the pain, bloating, and bowel frequency associated with IBS, and their use does not imply that IBS is caused by a mental health condition. Your gastroenterologist will discuss which options are most appropriate for your symptom pattern.
Psychological and behavioural therapies
Given the direct relationship between the brain and the gut, psychological therapies can be a genuinely effective part of IBS management. Cognitive behavioural therapy (CBT) and gut-directed hypnotherapy both have good evidence for reducing symptom severity. Relaxation techniques including meditation, exercise, deep breathing, and relaxation therapy may help reduce cramping, pain, and the frequency of flare-ups. For some patients, physiotherapy targeting pelvic floor function addresses a specific contributor to symptoms and can produce significant improvement. If you are experiencing significant anxiety, depression, or sleep difficulties alongside your IBS, it is important to raise these with your doctor.
Lifestyle factors
A number of everyday habits can influence the frequency and severity of IBS symptoms. Maintaining a consistent eating routine and avoiding sudden changes to your daily patterns can help keep symptoms more predictable and manageable. Regular physical activity supports overall gut function. Being mindful of alcohol intake, caffeine consumption, and smoking is also worthwhile, as all three can aggravate symptoms in susceptible individuals. Keeping a food and symptom journal helps identify personal patterns and gives your clinical team valuable information to guide your management.
Complications and wider impact of IBS
IBS does not damage the colon or other parts of the digestive system, and it does not lead to bowel cancer or other serious bowel conditions. However, it can have a meaningful impact on quality of life. Chronic symptoms, unpredictability, and the need to organise daily activities around bowel function can take a real toll. Some people with IBS also experience associated conditions including headaches, migraines, period pain, fibromyalgia, urinary symptoms, and chronic fatigue. The reasons for these associations are not fully understood, but they reflect the broad systemic effects that can accompany a sensitised gut.
If IBS is affecting your mood or mental health, support is available. Discussing IBS-specific psychological services with your doctor is a reasonable and worthwhile step.
A small number of people with IBS may experience episodes of faecal incontinence. Continence Health Australia can provide practical strategies and support, and their helpline is available on 1800 33 00 66.
Reducing the frequency of symptoms
While IBS cannot be cured, most people find they can substantially reduce the frequency and severity of flare-ups by identifying and managing their individual triggers. Maintaining consistent eating patterns, keeping physically active, moderating known dietary aggravants, managing stress, and working with your healthcare team to refine your approach over time all contribute to better long-term symptom control. You are not alone in managing this condition, and a structured lifestyle and treatment plan makes a real difference for most people.
Specialist care for IBS at Queensland Gastroenterology
A diagnosis of IBS deserves the same careful attention as any other gastrointestinal condition. Our gastroenterology specialists take a thorough, evidence-based approach to ruling out other causes and developing a practical, personalised management plan.
If you are experiencing ongoing bowel symptoms and are looking for answers, we encourage you to speak with your GP about a referral.
If you have received a referral to see one of our doctors, you can request an appointment, or contact our rooms directly on (07) 3321 1500.
This information has been sourced and adapted from education resources developed by
