Irritable Bowel Syndrome: When the Gut Hurts but the Tests Are Normal
Irritable bowel syndrome is a long-term condition in which the gut is oversensitive and its muscle contractions are poorly coordinated, producing abdominal pain that is linked to opening the bowels or to a change in stool frequency or form. Bloating, urgency, a feeling of incomplete emptying and mucus are common; bleeding, weight loss and night-time waking are not, and point to something else. The gut looks normal on tests, which is why it was long dismissed, but the pain is genuine and comes from real changes in gut nerve signalling, gut movement and the gut bacteria. It is diagnosed positively from the symptom pattern with a small set of blood tests, not by scanning everything. Treatment works best in layers: regular meals and identifying personal food triggers, soluble fibre such as ispaghol husk for constipation, antispasmodics for pain, targeted medicines for the dominant bowel pattern, and psychological therapies that act on the gut-brain link and have some of the strongest long-term evidence of anything on the list.
Health writers · Aslam Clinic
What is going wrong
The gut has its own nervous system — hundreds of millions of nerve cells lining the bowel wall — in constant two-way conversation with the brain. In irritable bowel syndrome that conversation is miscalibrated. Ordinary amounts of gas and ordinary stretching of the bowel wall register as pain, a phenomenon called visceral hypersensitivity. At the same time the contractions that move contents along become irregular: too fast in some people, producing looseness and urgency, too slow in others, producing constipation and bloating.
Several things feed into that. A bout of severe gastroenteritis can leave a persistently sensitive gut behind — post-infectious IBS, a common story here after a bad episode of food or water-borne illness, sometimes severe enough at the time to have caused . The mix of in the bowel differs measurably from that of people without IBS. Low-grade in the bowel lining is present in some. And sustained stress genuinely alters gut movement and sensitivity through hormonal and nerve pathways, which is why symptoms flare around exams, weddings, bereavement or job loss.
What is not happening matters just as much. IBS does not damage the bowel, does not become , does not shorten life, and does not turn into inflammatory bowel disease. That is not a consolation prize; it is genuinely useful information, because much of the distress of IBS is fear of what is being missed.
How it is diagnosed
The internationally used definition, the Rome IV criteria, describes recurrent abdominal pain on average at least one day a week over the last three months, associated with at least two of the following: it is related to opening the bowels; it comes with a change in how often you go; or it comes with a change in the form of the stool. Symptoms should have started at least six months earlier. That is a positive description of a pattern, not a diagnosis of last resort.
Alongside it your doctor will run a small number of tests — a , an inflammation marker such as CRP, and coeliac antibodies, since coeliac disease is a treatable condition that mimics IBS closely. Where inflammatory bowel disease is a serious part of the , a stool test called faecal calprotectin separates the two well. In Pakistan a stool examination for parasites is often added, because giardia and amoebic infection are common and produce a very similar picture; a treatable infection found this way is a far better outcome than a lifetime label.
| Type | Predominant stools | Usual first steps |
|---|---|---|
| IBS with constipation | Hard or lumpy more than a quarter of the time, loose rarely | Soluble fibre such as ispaghol, fluid, movement, an osmotic laxative that is not lactulose |
| IBS with diarrhoea | Loose or watery more than a quarter of the time, hard rarely | Identifying triggers, loperamide before predictable situations, soluble fibre |
| Mixed IBS | Both hard and loose stools more than a quarter of the time | Regular meals, antispasmodics for pain, treating whichever pattern dominates that month |
Food: what to change and what not to
The commonest mistake is cutting out a long list of foods at once. It rarely identifies anything, it makes eating with family miserable, and over months it narrows the diet enough to cause real nutritional problems. Change one thing at a time, give it two to four weeks, and keep a simple diary.
- Eat at regular times and do not skip meals. The bowel responds to routine, and long gaps followed by a large plate provoke cramping.
- Slow the meal down. Eating quickly swallows air, which is a large part of bloating.
- Limit strong chai and coffee to around three cups a day, and cut fizzy drinks, which add gas directly.
- Reduce fried and very fatty food — parathas, samosas, heavy oily salan — which stimulate a strong bowel reflex after eating.
- Test spicy food properly. Chilli genuinely worsens pain and urgency in some people and does nothing in others. Two weeks off, two weeks on, is a fair test.
- Be careful with sugar-free products. Sorbitol, mannitol and xylitol in chewing gum and diabetic sweets are potent causes of bloating and looseness.
- Consider a low FODMAP trial, but only with a dietitian. It helps roughly half to three-quarters of people in trials, but it is a restrictive short-term elimination followed by structured reintroduction. Done alone and left in place indefinitely, it does harm.
On fibre, the distinction matters more than the quantity. Soluble fibre — ispaghol or isabgol husk, the psyllium sold in every Pakistani pharmacy and grocery — helps IBS and is recommended in guidelines. Insoluble fibre such as wheat bran makes it worse in many people and should not be added. Start with a small amount of ispaghol in a full glass of water once a day, take it with plenty of fluid, and build up over two to three weeks; increasing it quickly causes the bloating people then blame on the fibre itself.
Medicines that help
No single tablet treats IBS as a whole, which is why the medicines below aim at particular symptoms. All except loperamide and simple fibre are a prescriber's decision, and the choice depends on which symptom dominates and what else you take.
- Antispasmodics relax the bowel muscle and are used for cramping pain, often before meals. Mebeverine and hyoscine are the familiar examples here.
- Peppermint oil capsules act as a natural antispasmodic with reasonable trial evidence for pain and bloating. Coated capsules are used so the oil is released past the stomach, since uncoated peppermint can worsen heartburn.
- Laxatives for constipation-predominant IBS, chosen to soften rather than stimulate. Lactulose is specifically avoided because it ferments and worsens bloating; an osmotic laxative such as macrogol is preferred.
- Loperamide for diarrhoea-predominant IBS, taken before a journey or an event rather than continuously, so it controls urgency without causing constipation.
- Low-dose tricyclic antidepressants, used here not for mood but because at low doses they dampen gut pain signalling and slow the bowel. The dose is far below an antidepressant dose, and that should be explained rather than discovered on the leaflet; dry mouth and drowsiness are the usual .
- Probiotics, where the evidence is mixed. A single product taken for at least four weeks and stopped if nothing changes is reasonable; several at once for months is not, and much of the reported benefit is no better than .
One thing not on that list is repeated courses of antibiotics for undiagnosed loose stools. It is extremely common here, it is rarely justified without a confirmed infection, and it damages the gut bacteria in a way that can worsen IBS while contributing to that affects everyone. If diarrhoea is prolonged, ask for a stool test rather than another course.
The gut-brain part, taken seriously
Being told that bowel symptoms are stress-related is often heard as being told they are not real. That is not what the evidence says. Cognitive behavioural therapy adapted for IBS and gut-directed hypnotherapy both produce measurable improvements in pain, bowel habit and quality of life, and the benefit persists for a year or more after the sessions stop — a durability few tablets can claim. They work by changing how gut and brain signal to each other, which is a physical mechanism, not a moral one.
Practical versions of the same principle help even without formal therapy: regular sleep, twenty to thirty minutes of walking on most days, breathing exercises when symptoms spike, and treating an untreated anxiety or depressive illness if one is present. Physical activity improves IBS symptoms in its own right.
When to see a doctor
See a doctor to have the diagnosis made properly in the first place, rather than assuming it. Come back if the pattern changes — new bleeding, weight loss, night-time symptoms, fever — because a previous IBS diagnosis does not protect you from developing something else later, and that is a genuine trap. It is also why bowel cancer still applies to you at the usual age and risk thresholds, exactly as it would to anyone else.
Come back too if symptoms are controlling your life: taking days off, avoiding travel, planning routes around toilets. That is not something to endure quietly, and it is exactly where the layered approach above tends to work. If your main trouble is burning in the chest and a sour taste rather than abdominal pain, see our guide to acid reflux and heartburn — the two overlap in a large number of people.
Common questions
Still not sure what to do?
Reading about a symptom only goes so far. A doctor who can ask you questions and examine you will get further in ten minutes than any article can.
