IBS-C
Also called: IBS with constipation, constipation-predominant IBS
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 percent of bowel movements hard or lumpy and less than 25 percent 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
- Add 25 to 30 grams of fibre a day, mostly from oats, kiwi, flax, chia, psyllium, beans and pulses.
- Drink 2 litres of water across the day. Hydration is what makes fibre useful, not harder.
- Walk 30 minutes daily. NICE advises increasing physical activity in people with IBS.
- Try a 4-week low-FODMAP elimination under a dietitian if symptoms persist after the basics. Reintroduce systematically.
- Daily psyllium husk (ispaghula, around 5 to 10 g) if the basics aren't enough.
- 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 IBS-C patients 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.
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 patients 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
- NICE CG61: Irritable bowel syndrome in adults, diagnosis and management (Recommendations) (NICE)
- NICE DG11: Faecal calprotectin diagnostic tests for inflammatory diseases of the bowel (Clinical need and practice) (NICE)
- Rome IV Diagnostic Criteria for IBS (Rome Foundation)
- Schmulson & Drossman 2017, Update on Rome IV Criteria for Colorectal Disorders (IBS-C subtyping >25% hard / <25% loose) (J Neurogastroenterol Motil (PMC))
- Monash University, The 3 phases of the low FODMAP diet (Monash University)
- Black et al 2021, A Low-FODMAP Diet Improves the Global Symptoms and Bowel Habits of Adult IBS Patients: Systematic Review and Meta-Analysis (Front Nutr (PMC))
- Whorwell et al 2006, Efficacy of an encapsulated probiotic Bifidobacterium infantis 35624 in women with IBS (Am J Gastroenterol (PubMed))
- Chang & Heitkemper 2010, Meta-analysis: do IBS symptoms vary between men and women? (Aliment Pharmacol Ther (PMC))
- AGA-ACG Clinical Practice Guideline: Pharmacological Management of Chronic Idiopathic Constipation (linaclotide, plecanatide, prucalopride) (Gastroenterology / Am J Gastroenterol (PMC))
- Bharucha & Lacy 2016, Chronic Constipation and Constipation-Predominant IBS: Separate Disorders or a Spectrum? (Therap Adv Gastroenterol (PMC))
- Rey et al 2007, Change over time of bowel habit in IBS: 1-year follow-up (RITMO study) (Aliment Pharmacol Ther (PubMed))