Written by Megan Jackson, specialist pelvic health physiotherapist (HCPC registered, MCSP, POGP). Clinically reviewed and updated 30 May 2026.
Quick answer. Anismus (also called dyssynergic defaecation, or DD) is a treatable problem with how the abdominal and pelvic floor muscles coordinate during a bowel motion — not a problem with the bowel itself. Up to half of all people with persistent constipation have it.1 The evidence-based treatment is pelvic floor physiotherapy with biofeedback. Laxatives alone usually don’t fix it because the muscles, not the stool, are the bottleneck.
What is anismus?
Anismus is an older clinical word for what most specialists now call dyssynergic defaecation, and is a functional defaecation disorder. The two terms describe the same problem: the muscles of the pelvic floor — particularly the puborectalis and the external anal sphincter — fail to relax (and sometimes tighten further) at the very moment they need to let go for a bowel motion. The stool, the diet, the fluids, the fibre are all doing their job. The exit doors are stuck. Sometimes DD is called obstructive defaecation, which is true (although obstructive defaecation can have other causes also).
It is a coordination problem, not a strength problem. You can have a perfectly strong pelvic floor and still have anismus — in fact, an overly strong, overly braced pelvic floor is one of the more common patterns we see. The muscles work, they just work in the wrong direction at the wrong time. It is a slightly different issue to inadequate defaecatory propulsion, where the bowel itself fails to push effectively rather than the exit failing to open.
Anismus is surprisingly common but most people have never heard of it. Most have been treated for constipation as though it were a transit-time or stool-consistency problem — with stool softeners, with osmotic laxatives, sometimes for years — without anyone checking whether the muscles at the end of the process are doing what they should.
How a normal bowel motion is supposed to work
To pass a stool, three things have to happen at the same time. The bowel wall has to push (a coordinated wave of muscle contraction called peristalsis). The abdominal pressure has to rise (a controlled push, not a strain). And the pelvic floor — specifically the puborectalis sling that loops around the back of the rectum — has to relax and let go. When all three happen together, the rectum straightens, the anal sphincters open, and the stool passes without effort.
In anismus, the third step doesn’t happen — or worse, it reverses. The pelvic floor contracts when it should be relaxing. The puborectalis sling tightens its hold on the rectum, kinking it. The anal sphincter clamps down. The harder the person pushes, the more those muscles brace in defence. The bowel is shouting “go” and the doors are saying “no”.
How do I know if I have it?
Anismus rarely presents with a single, neat symptom. It usually shows up as a cluster — and as a frustration that no single doctor or treatment has quite explained. The patterns we see most often are:
- Straining for long periods on the toilet with little or nothing to show for it.
- A persistent sense of incomplete emptying — “I went, but it doesn’t feel like I’m done”.
- Needing to support, splint or press around the perineum or vaginal wall to help things move (although vaginal prolapse can also cause this).
- Stools that get part-way through and then stop, or that come out as small fragments.
- Bowel motions that take a very long time — over 15 or 20 minutes is a flag.
- Symptoms that don’t improve, or get worse, with laxatives.
- Long history of “chronic constipation” or “IBS-C” without lasting change despite multiple treatments.
- Sometimes: pelvic pain, lower back pain, or pain at the tailbone after a bowel motion.
If several of those sound familiar, anismus is worth ruling in or out. Crucially, it’s not a diagnosis you can make with a scan or a blood test alone — it’s a clinical pattern that becomes obvious once someone watches what your pelvic floor is actually doing when you try to bear down.
Important. If you have noticed any rectal bleeding, unexplained weight loss, a change in bowel habit lasting more than three weeks (especially after the age of 50), persistent abdominal pain, or a family history of bowel cancer, please see your GP first. Anismus is a benign (but very limiting) muscle-coordination problem; the symptoms above are not.
Why does it happen?
In some people there is a clear trigger. In many, there isn’t one. Both pictures are common. The most frequent contributing factors are:
Learned toileting patterns
The way we use the loo is learned, often in childhood. Children who hold on for long periods at school, who avoid public toilets, who experience pain during or after a bowel motion, can develop a protective pattern of bracing the pelvic floor in anticipation. The pattern outlasts the original reason and becomes the default response years or decades later.
Pelvic pain, trauma or surgery
Conditions that cause persistent pain — back pain, endometriosis, vulvodynia, chronic prostatitis, post-surgical pain — often produce a protective tightening of the pelvic floor as a whole. That same protective tightening can stop the muscles releasing during defaecation.
Anxiety, stress and the nervous system
The pelvic floor is highly responsive to nervous system state. Sustained stress, anxiety, sleep disruption, and a history of trauma (including birth trauma) all tend to increase resting pelvic floor tone. This isn’t psychological in the dismissive sense — it’s the body’s normal physiological response to threat. But it does make defaecation harder.
After childbirth or surgery
Damage to the perineum during childbirth, episiotomies, third- or fourth-degree tears, and surgery in the pelvis (including hysterectomy and bowel surgery) can all change how the pelvic floor coordinates. Sometimes there’s weakness, sometimes there’s bracing in response to pain, often both at different times.
No clear cause at all
And sometimes — perhaps the most frustrating answer — there’s no identifiable trigger. The muscles have just learned the wrong pattern. The good news is that whether or not we can name the cause, the treatment is the same.
How is anismus diagnosed?
There is no single “anismus test”. Diagnosis combines clinical history, physical examination, and (sometimes) one or two specialist investigations.
Clinical history
A detailed conversation about symptoms is the most important part. How long has it been going on? How much do you strain? What does a typical bowel motion feel like? What helps? What makes it worse? Are there other pelvic symptoms — bladder, sexual, pain? The Rome IV criteria2,3 — an internationally agreed framework for functional bowel disorders — set out the formal definition, but most experienced clinicians can spot the pattern within a few minutes of listening.
Physical assessment by a pelvic health physiotherapist
A vaginal or rectal examination, with your explicit consent, lets us assess pelvic floor tone, strength, coordination and — most importantly — what happens when you bear down. In anismus, instead of feeling the muscles release, we feel them contract or fail to lengthen. Many patients with long-standing symptoms have never had this assessed properly. It is the single most informative test, and it can be done in a single appointment.
Specialist investigations (when relevant)
If you are under the care of a colorectal or gastroenterology service, you may be offered anorectal manometry (a small pressure probe that measures muscle activity), a balloon expulsion test (your ability to pass a small balloon from the rectum), or a defaecating proctogram (MRI). These investigations are useful in complex cases and can confirm the pattern. They are not always necessary, particularly when the clinical assessment is clear.
What treatment actually works?
The treatment hierarchy for anismus is well-established, evidence-based, and — for most people — successful within a few months. The order matters.
Step 1: lifestyle and toileting fundamentals
Even the strongest physiotherapy programme works better if the basics are in place. That means:
- Adequate fluid (around 1.5–2 litres a day for most adults).
- Adequate fibre (around 30 g a day, from food where possible — fruit, vegetables, whole grains, pulses) with dietician support where needed.
- A regular toileting window — typically 20–30 minutes after a meal, when the gastrocolic reflex is at its strongest.
- Optimised toileting posture — feet up on a stool, knees above hips, leaning slightly forward. This straightens the anorectal angle and reduces the work the pelvic floor has to do. Our toothpaste-tube analogy explains why.
- No straining — if nothing has happened in 5–10 minutes, get up and come back later. Long sits on the toilet are a risk factor for pelvic floor strain and haemorrhoids.
These changes alone won’t fix anismus, but they are part of the foundations of treatment.
Step 2: pelvic floor physiotherapy with biofeedback
This is the first-line treatment for anismus and dyssynergic defaecation in international guidelines.4,7 It works because anismus is fundamentally a learned coordination problem — and biofeedback retrains coordination.
A typical course involves four to eight sessions over two to three months. In each session we work on three things: down-training (teaching the pelvic floor to fully release, often using breath, position and visualisation), defaecation dynamics (practising the correct push-and-relax pattern, sometimes with a small sensor or with manual feedback), and rectal sensitivity training (helping you recognise the urge to go and trust it).
Published trials and meta-analyses consistently report meaningful improvement in 70–80% of patients who complete a structured biofeedback programme.5,6,7 That figure is substantially higher than for laxatives or for stool-softening alone.
Step 3: medical input, where indicated
In a small number of patients, physiotherapy alone is not enough. Options at this point include targeted medication (prokinetics, medications such as linaclotide or prucalopride, with gastroenterology input), botulinum toxin injection into the puborectalis (specialist colorectal clinics), or sacral nerve stimulation. Surgery is rarely the answer for anismus itself, though it may be appropriate if there is a co-existing structural problem such as a significant rectocele.
What does a course of pelvic health physiotherapy actually look like?
Most people aren’t sure what physiotherapy for anismus will actually involve. The honest answer: it is more talking, breathing, posture work and toileting practice than most people expect. Internal sensors are sometimes used — with your consent — when real-time feedback adds something the work without them can’t.
A typical first appointment lasts an hour. We talk through the whole picture — bowel, bladder, sexual function, pain, pregnancy and surgical history, current medication, work, stress and sleep. Then, with your consent, we carry out a focused physical assessment that may include observation of breath and movement, abdominal palpation, and (when clinically indicated) a vaginal or rectal examination to feel directly what the pelvic floor is doing during contraction, relaxation and a simulated bear-down.
You leave the first appointment with a working diagnosis, an honest estimate of how long things are likely to take, and a small number of things to start practising at home. Follow-up appointments review and progress that programme. We use real-time feedback (visual, tactile, sometimes equipment-based) so that you can feel and see what your pelvic floor is doing — that feedback is the active ingredient.
Most patients with anismus see a meaningful change within four to six sessions. More complex cases — long-standing symptoms, co-existing pelvic pain, or post-surgical patterns — typically take a longer course.
Why see a specialist pelvic health physiotherapist rather than a general physio?
Pelvic health physiotherapy is a recognised specialism, not a general physio skill. UK pelvic health physiotherapists complete dedicated post-registration training — usually through POGP (Pelvic, Obstetric and Gynaecological Physiotherapy) modules — and most have several years of dedicated clinical practice in the area. We can carry out the internal examination that confirms the diagnosis. We are trained in defaecation-specific biofeedback techniques. And we know when to escalate to colorectal, urogynaecology or gastroenterology colleagues.
At Pelvix we have been treating anismus and dyssynergic defaecation as a core clinical interest since the clinic opened. If you would like to find out more about how we approach the condition, our dedicated anismus and dyssynergic defecation page goes into the assessment and treatment process in detail.
Frequently asked questions
Is anismus the same as constipation?
No. Constipation is a symptom (infrequent or difficult bowel motions). Anismus is one possible cause of constipation — specifically, an outlet problem where the pelvic floor doesn’t relax during defaecation. Many people with anismus have been treated for general constipation for years without anyone checking the pelvic floor.
Can anismus be cured?
For most people, yes — with the right treatment. Pelvic floor physiotherapy with biofeedback is reported to produce meaningful improvement in around 70–80% of patients in published trials. “Cure” is the word patients often use; clinically we tend to talk about restoring normal coordination, which is what biofeedback retraining is designed to do.
Do I need a GP referral to see a pelvic health physiotherapist?
In the UK, no — you can self-refer to a private pelvic health physiotherapist directly. If your symptoms have already been investigated by a GP, colorectal team or gastroenterologist, we will happily liaise with them so the care joins up.
Will I need an internal examination?
Not always. A vaginal or rectal examination is the most accurate way to assess pelvic floor coordination and defaecation dynamics, but we will only suggest it if it’s clinically helpful and you will always be in full control of whether it happens. Many patients are assessed and treated effectively without one.
How many sessions will I need?
Most people see meaningful change within four to six sessions over two to three months. Long-standing symptoms, co-existing pelvic pain or post-surgical patterns may need a longer course. We give an honest estimate at the first appointment.
Will laxatives help?
Laxatives soften the stool or speed up transit — they don’t change what the pelvic floor is doing. In anismus, the bottleneck is at the exit, not in the bowel. Laxatives can sometimes help in the short term while the muscular pattern is being retrained, but they are not a long-term solution on their own.
Is anismus linked to IBS?
They often overlap. People diagnosed with IBS — particularly the constipation-predominant subtype (IBS-C) — frequently have an unrecognised defaecatory dysfunction. A pelvic health assessment can identify the difference.
Can men get anismus?
Yes. Anismus and dyssynergic defaecation affect men and women. The assessment and treatment principles are the same.
Is the treatment painful or invasive?
No. Pelvic health physiotherapy is not meant to be painful or invasive. Many of the most useful exercises involve breath, posture and toileting position, and can be practised entirely at home.
Are you covered by my health insurance?
We are recognised by most major insurers. Please get in touch to discuss your individual arrangements, or you can book online.
Ready to be assessed?
If you have read this far, the chances are this is a problem you have been carrying for a while. Pelvic health physiotherapy with biofeedback is an evidence-based, well-tolerated, and (for most people) effective treatment for anismus and dyssynergic defaecation.
Book a free 15-minute introductory phone call to talk through whether assessment is the right next step, or book an initial appointment directly.
About the author. Megan Jackson is a specialist pelvic health physiotherapist and the founder of Pelvix Specialist Pelvic Physiotherapy in Keynsham, serving Bristol and Bath. HCPC registered, Chartered Society of Physiotherapy member, POGP associate. Dyssynergic defaecation and anismus are core clinical interests; Pelvix has been treating the condition since the clinic opened in 2022. Read more about Megan.
References
- Rao SS, Patcharatrakul T. Diagnosis and Treatment of Dyssynergic Defecation. J Neurogastroenterol Motil. 2016;22(3):423–435. doi:10.5056/jnm16060
- Lacy BE, Mearin F, Chang L, et al. Bowel Disorders (Rome IV). Gastroenterology. 2016;150(6):1393–1407.
- Rao SSC, Bharucha AE, Chiarioni G, et al. Functional Anorectal Disorders (Rome IV). Gastroenterology. 2016;150(6):1430–1442.
- Bharucha AE, Lacy BE. Mechanisms, Evaluation, and Management of Chronic Constipation. Gastroenterology. 2020;158(5):1232–1249.e3.
- Chiarioni G, Whitehead WE, Pezza V, Morelli A, Bassotti G. Biofeedback is superior to laxatives for normal transit constipation due to pelvic floor dyssynergia. Gastroenterology. 2006;130(3):657–664. doi:10.1053/j.gastro.2005.11.014
- Bassotti G, Chistolini F, Sietchiping-Nzepa F, Roberto GD, Morelli A, Chiarioni G. Biofeedback for pelvic floor dysfunction in constipation. BMJ. 2004;328(7436):393–396. doi:10.1136/bmj.328.7436.393
- Skardoon GR, Khera AJ, Emmanuel AV, Burgell RE. Review article: dyssynergic defaecation and biofeedback therapy in the pathophysiology and management of functional constipation. Aliment Pharmacol Ther. 2017;46(4):410–423.
- Heitmann PT, Vollebregt PF, Knowles CH, et al. Understanding the physiology of human defaecation and disorders of continence and evacuation. Nat Rev Gastroenterol Hepatol. 2021;18(11):751–769.