IBS-C

Also called IBS with constipation, constipation-predominant IBS.

Dr Chad OkayFounder, Suna Health

3 min read. Updated .

IBS-C is the constipation-predominant subtype of irritable bowel syndrome. People with IBS-C have abdominal pain related to defecation, with more than 25% of bowel movements hard or lumpy and less than 25% loose. About a third of all IBS cases sit in this subtype. The fix is usually a combination of soluble fibre, hydration, movement and (sometimes) targeted medication.

How IBS-C is diagnosed

IBS-C is a clinical diagnosis using the Rome IV criteria: recurrent abdominal pain at least 1 day a week for 3 months, related to defecation, with a stool-form pattern that is mostly hard or lumpy (Bristol stool types 1 to 2) and rarely loose (types 6 to 7). Coeliac disease, inflammatory bowel disease, and other organic causes are ruled out with blood tests, faecal calprotectin and (in some cases) colonoscopy.

What it feels like

  • Bloating that builds through the day and eases overnight.
  • Hard, lumpy or pellet-like stools, often with strain.
  • A feeling of incomplete emptying after a bowel movement.
  • Cramping that improves after going.
  • Fewer than 3 bowel movements a week, often.
  • Symptoms cluster around stress, hormonal cycles, and certain foods (FODMAPs).

What helps

  1. Add 25 to 30 grams of fibre a day, mostly from oats, kiwi, flax, chia, psyllium, beans and pulses.
  2. Drink 2 litres of water across the day. Hydration is what makes fibre useful, not harder.
  3. Walk 30 minutes daily. NICE advises increasing physical activity in people with IBS.
  4. Try a 4-week low-FODMAP elimination under a dietitian if symptoms persist after the basics. Reintroduce systematically.
  5. Daily psyllium husk (ispaghula, around 5 to 10 g) if the basics aren't enough.
  6. Consider prescribed laxatives (linaclotide, plecanatide, prucalopride) under specialist care if lifestyle and OTC options have failed.

What does not help

  • Insoluble fibre such as wheat bran. NICE advises people with IBS be discouraged from it because it can worsen symptoms.
  • Senna or stimulant laxatives daily. Useful as rescue, but routine long-term use is not advised.
  • Cutting all fermented foods. Most people with IBS-C tolerate them fine; the problem is FODMAPs in specific foods, not fermentation generally.
  • Probiotics without a strain target. Some strains (especially B. infantis 35624) help; most don't move the needle.

When constipation needs more than fibre

If you have stopped passing stool or wind altogether and your tummy is swollen with vomiting, that combination is an emergency whatever your usual pattern: 999 in the UK, 911 in the US. An IBS-C label should never absorb anything new: bleeding, weight going down on its own, unexplained anaemia, or a changed habit that has not settled deserve a doctor's look at any age (the FIT test has no minimum duration), new patterns after 50 deserve one before being filed under IBS, and what used to work no longer working is a reason for a review, not a bigger fibre dose.

Common questions

What's the difference between IBS-C and just being constipated?
IBS-C requires abdominal pain that is related to defecation. Functional constipation can have hard stools without that pain pattern. The treatment overlaps but IBS-C also benefits from low-FODMAP and gut-brain therapies that don't change ordinary constipation.
Can IBS-C turn into IBS-D?
Yes. IBS subtypes can switch over time, often around stress, illness, or after antibiotics. Subtype changes are common over time. In a 1-year follow-up study only about a third of people kept the same bowel habit throughout, with most shifts to or from mixed or unsubtyped IBS.
Does IBS-C affect women more than men?
Yes, by about 2 to 1. Hormonal influence on gut motility (especially in the luteal phase) is part of the reason. Many women find their IBS-C cycles with their periods.
Is IBS-C the same as slow transit constipation?
Related but not identical. Slow transit constipation is mainly a colonic transit problem. IBS-C more often involves visceral hypersensitivity (the same gas and stool feels more painful), though the two overlap and the physiological differences are not clear-cut. Diagnosis is clinical.

Sources

Written by Dr Chad Okay. Contributor: Dr Parisah Hussain, MBChB, BSc (Hons), DRCOG, MRCGP. Last updated 17 September 2026. From Digests.

Digests explains how the body works in general, everyday terms. It is not medical advice. It is not a substitute for someone who can examine you and knows your history, and we do not tell you what dose of any medicine to take.

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