Irritable bowel syndrome (IBS) is a common, long-term disorder of gut-brain interaction that causes recurring belly pain along with diarrhea, constipation, or both. There's no cure yet, but clinical guidelines support several treatments that ease symptoms, including the low-FODMAP diet, soluble fiber, peppermint oil, and gut-directed psychological therapies.[1][2][3] Below are short, sourced answers to the questions people ask most.
IBS basics
What is IBS?
IBS is a common long-term condition that causes recurring abdominal pain linked to changes in your bowel habits: diarrhea, constipation, or both.[1] Doctors now call it a disorder of gut-brain interaction, because the gut and brain don't communicate normally, which can make the gut more sensitive and change how it moves.[3][1] IBS is grouped by your main stool pattern into IBS with constipation (IBS-C), IBS with diarrhea (IBS-D), mixed (IBS-M), or unclassified (IBS-U).[4]
How common is IBS, and who gets it?
Very common — a pooled analysis of 80 population studies found that about 11% of adults worldwide (roughly 1 in 10) met the definitions of IBS used at the time, and women were about 1.7 times as likely as men to have it.[5] Under the stricter Rome IV criteria, 4.1% of adults qualified in a 33-country internet survey.[6] IBS is also less common after age 50.[5]
What causes IBS?
There's no single cause. In IBS the gut and brain communicate abnormally, which leads to changes in how the gut moves, an oversensitive gut, and altered pain processing; gut bacteria, genes, and immune changes may also play a part.[1] The best-documented trigger is a gut infection: in a meta-analysis of 45 studies, 10.1% of people had IBS 12 months after infectious gastroenteritis, about four times the usual risk.[7]
Is IBS curable?
No — not yet, but it is treatable. For most people IBS follows a relapsing and remitting course, with better and worse spells over time.[1] Guidelines support a range of options, including diet changes, soluble fiber, psychological therapies, and medicines matched to your main symptoms, so the realistic goal is finding the combination that keeps your symptoms under control.[2][3]
IBS symptoms and diagnosis
How is IBS diagnosed?
Usually from your symptoms plus a few simple tests, since no single test confirms IBS. Under the Rome IV criteria, IBS means abdominal pain on average at least one day a week over the last three months, linked to two or more of the following: bowel movements, a change in how often you go, or a change in how your stool looks, with symptoms that started at least six months earlier.[4] US guidelines favor this positive, symptom-based diagnosis over long rounds of tests to rule everything else out, and suggest a celiac blood test and a stool calprotectin test if you have diarrhea.[2] The newer Rome V criteria, published in 2026, loosen some of these rules, for example by counting abdominal discomfort as well as pain.[8]
What symptoms are red flags that it might not be IBS?
Unintentional weight loss, rectal bleeding or blood in your stool, unexplained iron-deficiency anemia, symptoms that start after about age 50, and a family history of bowel cancer, inflammatory bowel disease, or celiac disease are all warning signs.[9][1][2] They don't mean something serious is wrong, but they do mean you should see a doctor rather than assume it's IBS. See the full list of IBS red flags.
Can IBS cause weight loss?
Not usually — in a study of 330 people with IBS, body weight was no different from that of healthy volunteers, and most were normal weight or overweight.[10] Unintentional weight loss is a warning sign that guidelines say needs a doctor's assessment, because it can point to a different condition.[2][1] If you're losing weight because you've cut out many foods, a registered dietitian can help you widen your diet without setting off symptoms.
Does IBS show up on a colonoscopy?
No — there's no colonoscopy finding that confirms IBS; the diagnosis is based on your symptom pattern, and a colonoscopy is used to rule out other conditions.[9][4] The American College of Gastroenterology recommends against routine colonoscopy for people under 45 with IBS symptoms and no warning signs.[2] Your doctor may still advise one if you have red flags or are due for age-appropriate colorectal cancer screening.[9]
Does IBS increase your risk of colon cancer?
No — IBS hasn't been linked to a higher long-term risk of colorectal cancer. In a Danish study of 57,851 people with IBS, cancer risk was raised only in the first three months after diagnosis, most likely because some cancers were first mistaken for IBS, and it was lower than expected one to 10 years later.[11] That early spike is why new symptoms after about age 50 or other warning signs deserve proper investigation, and why an IBS diagnosis doesn't replace routine screening.[9]
Is IBS the same as IBD?
No — they are different conditions that can cause similar symptoms. Inflammatory bowel disease (IBD), which includes Crohn's disease and ulcerative colitis, involves inflammation that can damage the bowel, whereas IBS is a disorder of gut-brain interaction.[3] Because the two can look alike, US guidelines suggest a stool test called fecal calprotectin, a marker of gut inflammation, for people with suspected IBS and diarrhea; compare them side by side in IBS vs IBD.[2]
What is the IBS-SSS?
The IBS-SSS (IBS Severity Scoring System) is a short questionnaire that combines ratings of pain, bloating, bowel habits, and the impact on daily life into a score out of 500.[12] Scores of 75 to 175 indicate mild IBS, 175 to 300 moderate, and over 300 severe; people without IBS score below 75, and a drop of 50 points reliably indicates improvement.[12] Because it gives you a number, it's a simple way to track whether a change is working; see how the IBS-SSS works.
Food and the low-FODMAP diet
Does the low-FODMAP diet work for IBS?
Usually, yes — FODMAPs (fermentable oligo-, di-, monosaccharides and polyols) are short-chain carbohydrates that are poorly absorbed and fermented in the gut, and cutting them back has more trial evidence than any other IBS diet.[13][14] A 2022 analysis of 13 randomized trials with 944 patients found the low-FODMAP diet ranked first for overall symptoms, abdominal pain, and bloating.[15] US and UK guidelines both support it, and UK guidelines recommend it as a second-line diet supervised by a trained dietitian, with FODMAPs reintroduced afterward.[2][3]
Is the low-FODMAP diet forever?
No — it's designed as three stages: a short period of FODMAP restriction, then reintroducing FODMAP groups to find out which ones trigger your symptoms, then a personalized long-term diet that limits only your own triggers.[16][17] In a follow-up study of 103 people, 57% still had satisfactory symptom relief after reintroduction, and their diets stayed nutritionally adequate.[18] Strict elimination isn't meant to be permanent, so plan your reintroduction with a dietitian.
How long does the elimination phase last?
Usually 2 to 6 weeks. Monash University's FODMAP research team recommends trialing the diet for 2 to 6 weeks and then reviewing how you feel, and key clinical trials used 3 to 4 weeks.[17][19][20] If your symptoms haven't improved by then, talk to your dietitian or doctor before restricting any further.
Are bananas low FODMAP?
It depends on ripeness — firm, slightly unripe bananas are low FODMAP, while ripe bananas are high in fructans, a type of FODMAP; Monash University found this when it re-tested bananas in 2017.[21] A small serving of ripe banana is still an option, and if you already tolerate ripe bananas well, there's no need to cut them out.[21]
Is coffee bad for IBS?
Not for everyone, but it's a common trigger. Caffeinated coffee stimulates the colon (in one study about as strongly as a meal, and 60% more than water), and coffee is among the foods people with IBS most often blame for their symptoms.[22][10] Monash University researchers say blanket bans aren't warranted; instead, test your own response, and remember that regular milk in a latte adds lactose.[23]
Is gluten the problem, or fructans?
Often it's the fructans. In a blinded trial of 59 people who believed they were sensitive to gluten (with celiac disease ruled out), fructans caused more symptoms than gluten, and gluten caused no more symptoms than placebo; foods that contain gluten often contain fructans too.[24] An earlier trial found gluten-specific effects in only 8% of participants once their FODMAP intake was reduced.[13] Feeling better without wheat doesn't prove gluten is the culprit, so ask your doctor about celiac testing before you cut gluten out.
IBS treatments
Do probiotics help IBS?
Maybe — the evidence is mixed and guidelines disagree. The American College of Gastroenterology suggests against probiotics for overall IBS symptoms because the evidence is of very low quality, while the British Society of Gastroenterology says they may help but no specific strain can be recommended.[2][3] If you try one, UK guidance is to take it for up to 12 weeks and stop if your symptoms don't improve.[3]
Does peppermint oil help IBS?
Yes, it can — US guidelines suggest peppermint oil for overall IBS symptoms, and UK guidelines say it may help overall symptoms and abdominal pain.[2][3] A 2022 meta-analysis of 10 trials with 1,030 patients found it worked better than placebo, with one extra person improving for roughly every four treated, but side effects were more common and the quality of evidence was very low.[25] Ask a pharmacist or doctor which product suits you.
Which fiber helps IBS: psyllium or bran?
Soluble fiber such as psyllium (ispaghula) helps; insoluble wheat bran often doesn't. In a primary-care trial of 275 people, 57% responded to psyllium in the first month versus 35% on placebo, while bran helped less consistently and people on bran were the most likely to drop out early, mainly because their symptoms got worse.[26] US and UK guidelines recommend soluble fiber, started low and increased gradually to limit bloating, and UK guidelines advise avoiding wheat bran.[2][3]
Do CBT and gut-directed hypnotherapy work for IBS?
Yes — a 2020 analysis of 41 randomized trials with 4,072 people found cognitive behavioral therapy (CBT) and gut-directed hypnotherapy both effective, with the largest evidence base of any psychological therapy.[27] In one trial, gut-directed hypnotherapy worked as well as the low-FODMAP diet, improving symptoms in 72% and 71% of people respectively.[28] UK guidelines strongly recommend IBS-specific CBT and gut-directed hypnotherapy when symptoms persist, and US guidelines say gut-directed psychotherapy can be used alongside diet and medicines rather than as a last resort.[3][2]
Does exercise help IBS?
Yes — UK guidelines advise regular exercise for everyone with IBS.[3] In a randomized trial, people coached by a physiotherapist to be more active improved their IBS-SSS score by 51 points, compared with 5 points in the control group, and were less likely to see their symptoms get worse.[29]
Living with IBS
Can stress cause IBS flares?
Yes — for many people, stress makes IBS symptoms worse, because IBS involves disordered communication between the gut and the brain.[1] In a study that followed 117 people with IBS for 16 months, chronic life stress strongly predicted later symptom severity, and no one facing a highly threatening ongoing stressor improved by 50%.[30] That gut-brain link is also why CBT and gut-directed hypnotherapy can ease physical symptoms.[27]
Does IBS get worse during your period?
Often, yes — increases in abdominal pain, bloating, and changes in bowel habits have been reported just before and during menstruation, in women with and without IBS.[31] A review suggests the drop in estrogen and progesterone at those times may contribute, and one study found that women with IBS were more sensitive to gut pain during menstruation.[31] Logging your cycle alongside your symptoms in an IBS diary can help you separate hormonal flares from food reactions.
Can children get IBS?
Yes — a meta-analysis of 58 studies covering 196,472 children aged 4 to 18 found that IBS was the most commonly reported functional abdominal pain disorder, with a pooled prevalence of 8.8%.[32] Doctors use child-specific Rome criteria to diagnose it.[33] Because children are still growing, restrictive diets such as low-FODMAP should only be tried with guidance from a pediatrician and a pediatric dietitian.
About IBS Clue
What is IBS Clue?
IBS Clue is an iPhone app, coming soon to the App Store, that helps you follow a low-FODMAP plan and find your personal trigger foods. You snap a photo of a meal or type it in, and its AI identifies the dish and its ingredients, including hidden ones like garlic and onion in sauces, and estimates the meal's level in each of the six FODMAP groups. It's a self-tracking tool, not a medical device: it doesn't diagnose or treat IBS, and it screens for alarm features at sign-up and advises you to see a doctor if any apply. Read more about AI tools for IBS.
How does IBS Clue find my trigger foods?
It looks for patterns in your own diary. Symptoms within 6 hours of a meal count as a reaction, and a Bayesian logistic regression ranks your "Suspects" (the FODMAP groups most likely to be your triggers), adjusting for the other groups and for stacking from meals in the previous 4 hours, and gives a probability for each group. Results from structured reintroduction outrank these estimates, because a deliberate test is stronger evidence than a pattern in a food diary.
Does IBS Clue guide the low-FODMAP diet?
Yes — it walks you through three phases: elimination (usually 2 to 6 weeks), reintroduction of one FODMAP group at a time over 3 days with increasing amounts, and then personalization. It also includes the IBS-SSS questionnaire with weekly re-checks, quick symptom check-ins (bloating, pain, diarrhea, constipation, gas, and fatigue, with severity), and a Bristol stool log, and it exports a PDF report you can share with your doctor.
Is my data private in IBS Clue?
Yes — there's no account to create, and your data stays on your phone. Meal photos or descriptions are sent to the AI for analysis only after you give consent.
How much does IBS Clue cost, and which languages does it support?
IBS Clue is free, with an optional Pro subscription, and your first 10 AI meal analyses are free. It's available in 10 languages: English, Simplified Chinese, Traditional Chinese, Japanese, Korean, Thai, Spanish, French, German, and Portuguese.