IBS-C, or irritable bowel syndrome with constipation, is one of the main types of IBS. It isn't just constipation. People with IBS-C also have recurring abdominal pain, and often bloating, that are tied to their bowel habits. That combination is what separates it from ordinary constipation, and it's why the approach to diet and treatment is a little different.
This guide covers what IBS-C is, the typical symptoms, how it's diagnosed, the diet changes with the best evidence, and the treatments doctors use.
What Is IBS-C?
IBS is diagnosed using a set of criteria called Rome IV. You have IBS if you've had recurring abdominal pain linked to bowel movements, along with a change in how often you go or what your stool looks like. Doctors then classify the subtype by your most common stool type.1
In IBS-C, hard or lumpy stools are the main pattern and loose stools are uncommon. If both hard and loose stools happen often, that's IBS-M (mixed). If loose stools dominate, it's IBS-D. Our guide to IBS-D vs IBS-C compares the subtypes, and alternating constipation and diarrhea covers IBS-M.
IBS-C vs chronic constipation
The two overlap a lot, and some experts see them as points on the same spectrum. The main difference is pain: in IBS-C, abdominal pain is a core symptom and usually improves or changes with a bowel movement. In functional constipation, pain isn't a main feature.1
IBS-C Symptoms
- Abdominal pain or cramping, often eased or changed by a bowel movement
- Hard, dry or lumpy stools
- Going less often than usual
- Straining, or feeling that you haven't fully emptied your bowel
- Bloating and a swollen-looking belly, often worse later in the day
- Gas and abdominal discomfort after meals
Symptoms tend to come and go in flares. For managing bad days, see IBS flare-ups.
Blood in your stool or black stools, unintended weight loss, symptoms that wake you at night, new symptoms after about age 50, a family history of bowel cancer, celiac disease or inflammatory bowel disease, or a sudden change in bowel habits. These need checking before assuming IBS.
What Causes IBS-C?
There's no single cause. In IBS-C, gut contents often move more slowly through the colon, which lets more water be absorbed and makes stools harder. On top of that, the gut is often more sensitive to normal amounts of gas and stretching, so bloating feels worse. Stress, diet, sleep and the gut-brain connection all play a part. Read more in our guide to the gut-brain connection and IBS.
Some people with constipation have high methane levels on a breath test. Methane is linked with slower transit and constipation.7 High methane is now often called intestinal methanogen overgrowth (IMO). If your symptoms suggest it, your doctor may consider breath testing. See our SIBO diet guide for how this connects to diet.
IBS-C Diet: What Helps
1. Soluble fiber, especially psyllium
Fiber type matters more than the amount. Soluble fiber such as psyllium forms a gel that softens hard stool. In a randomized trial in primary care, psyllium improved IBS symptoms compared with placebo, while bran did not.4 US guidelines recommend soluble fiber for IBS symptoms.2 Insoluble fiber like wheat bran can make bloating and pain worse for many people with IBS. Start low and increase slowly. Our psyllium guide explains how.
2. Kiwi
In a trial in US adults with chronic constipation, green kiwifruit improved stool frequency, consistency and straining, and also improved bloating. It had the fewest side effects of the three options tested, which also included prunes and psyllium.6 That trial looked at chronic constipation, not IBS-C specifically, but kiwi is also low FODMAP, which makes it a sensible fruit to try.
Prunes worked too, but prunes are high in sorbitol, which can cause gas and bloating in IBS. Kiwi is usually the gentler choice.
3. A low FODMAP diet, carefully
The low FODMAP diet has the strongest evidence of any diet for IBS overall5, and it can reduce bloating and pain in IBS-C. Most trials included people with different IBS types, so the evidence for IBS-C alone is less clear.
There's one catch for IBS-C. Cutting wheat, beans and some fruits can reduce your fiber intake, which can make constipation worse. If you try the diet, keep fiber up with low FODMAP sources:
- Oats and quinoa
- Chia seeds and ground flaxseed
- Kiwi, oranges and blueberries
- Carrots, green beans, spinach and potatoes with the skin on
- Brown rice and buckwheat
Keep the elimination phase short and move on to reintroduction, so your diet stays as varied as possible. A dietitian can help balance FODMAPs and fiber. Start with our beginner's guide.
4. Fluids and regular meals
Fiber works best with enough fluid, so drink regularly through the day, especially when you add psyllium. Regular meals, including breakfast, help, because eating triggers the reflex that gets the colon moving. Our low FODMAP breakfast ideas are a good place to start.
IBS constipation foods to limit
- Wheat bran and bran cereals, which can increase bloating
- High FODMAP foods that cause gas, such as onion, garlic and beans, if they bother you
- Sugar alcohols in "sugar-free" products, which cause gas
- Very large, fatty meals, which can slow the stomach
Coffee can help some people with constipation by stimulating the colon. If you tolerate it, there's no need to cut it out. See coffee and IBS.
IBS-C Treatment
Physical activity
In a randomized trial, people with IBS who increased their physical activity had better symptoms than those who didn't.8 Walking, cycling or swimming most days is a practical start.
Over-the-counter options
Psyllium is usually the first step. Osmotic laxatives such as polyethylene glycol (PEG) draw water into the bowel to soften stool, and the American Gastroenterological Association conditionally recommends them for IBS-C.3 PEG can help stool frequency but may not ease pain or bloating. Stimulant laxatives can cause cramping. Talk to a pharmacist about which fits you. More in OTC options for IBS.
Prescription medications for IBS-C
If symptoms continue, a doctor may prescribe a medication. The American Gastroenterological Association's 2022 guideline strongly recommends linaclotide, and conditionally recommends tenapanor, plecanatide, tegaserod (no longer sold in the US) and lubiprostone. These work in different ways, mostly by increasing fluid in the gut or speeding transit. The same guideline conditionally recommends tricyclic antidepressants and antispasmodics for pain, and advises against SSRIs for IBS-C.3 Availability differs by country, and side effects vary, so this is a conversation to have with your doctor.
Gut-directed psychological therapies
Cognitive behavioral therapy and gut-directed hypnotherapy target the gut-brain connection. US guidelines recommend gut-directed psychotherapies for IBS symptoms.2 They can be used alongside diet and medication.
Toilet habits
Small habits help: give yourself unhurried time, try going at the same time each day (often after breakfast), and don't ignore the urge. Raising your feet on a small stool while sitting changes your posture in a way many people find makes it easier to pass stool.
A Sample IBS-C Day
- Breakfast: oat porridge with lactose-free milk, chia seeds and kiwi, with water
- Lunch: quinoa salad with chicken, carrot, spinach and a lemon and olive oil dressing
- Snack: an orange and a few walnuts
- Dinner: salmon with potatoes (skin on) and green beans
- Movement: a walk after dinner
For a full week, see our 7-day low FODMAP meal plan.
Common Questions
Can IBS-C turn into IBS-D?
Your subtype can change over time. Some people move between patterns, which is when IBS-M is considered. Tracking your stools over a few weeks helps your doctor classify it.1
What is the best diet for IBS-C?
There isn't one diet that works for everyone. The approaches with the most support are soluble fiber such as psyllium, enough fluid, regular meals, and a carefully planned low FODMAP diet that keeps fiber intake up.
Is IBS-C serious?
IBS-C doesn't damage the bowel or raise the risk of bowel cancer, but it can seriously affect quality of life. Get any warning signs checked, and ask for help if symptoms are getting in the way of daily life.
Does bloating mean IBS-C?
Not on its own. Bloating is common in all IBS types and in many other conditions. See foods that cause bloating for the food side.
Tracking your meals, stools and symptoms is the fastest way to see what works for your IBS-C. An IBS food diary or the Stummy app makes that easier, and you can check any food's FODMAP level in our FODMAP checker.
