What is the difference between constipation and faecal impaction?

Constipation means passing stool less often or with difficulty. Faecal impaction is a more severe stage where a hard, dry mass of stool becomes stuck and cannot be passed on its own, usually needing medical help to clear it.

Why do I have diarrhoea if I am actually blocked up?

This is called overflow diarrhoea: watery stool higher up leaks around the hard, stuck lump. It is a sign of impaction, not a simple stomach bug, so it should be checked by a doctor rather than treated with anti-diarrhoeal medicines.

My elderly parent has not passed stool for days and is now vomiting with a swollen, painful tummy — what should I do?

These can be signs of a bowel obstruction, which is an emergency. Seek urgent care immediately — in Singapore call 995 or go to A&E.

Can I clear an impaction myself with laxatives from the pharmacy?

It is safer to be assessed first, because impaction often needs specific treatment (such as suppositories, enemas or manual removal) done under guidance, and the wrong approach can worsen things. See a doctor, who can clear it safely and set up a plan to prevent it returning.

How can I stop it happening again?

Focus on prevention: enough dietary fibre, plenty of fluids, staying as active as possible, and a regular toilet routine. If you take medicines that cause constipation (like opioid painkillers), ask your doctor about a bowel regimen to go with them.

Faecal Impaction in Singapore: Overflow & Red Flags

Written & reviewed by the BestDoctors.sg editorial team · Last updated 25 Aug 2026 · General information, not medical advice

Faecal impaction is a large, hard, dry mass of stool that becomes stuck in the rectum (or lower colon) and cannot be passed. It is usually the end result of long-standing constipation: stool that sits too long has more water absorbed from it, becoming progressively harder until it can no longer move. It is most common and most serious in older, frail, bed-bound or immobile people. A crucial and often-missed feature is overflow diarrhoea — watery stool leaking around the blockage, which can be mistaken for ordinary diarrhoea.

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In a medical emergency, or for severe or sudden symptoms such as breathing difficulty, chest pain, fainting or stroke signs, call 995 immediately.

Severe abdominal pain, a swollen, tender abdomen, vomiting, and not passing any stool OR wind can mean bowel obstruction — a surgical emergency; call 995 or go to A&E. New watery leakage in someone with chronic constipation is a warning sign, not a simple stomach bug.

What it is

Impaction is essentially the severe end of constipation, where a hard, dry lump of stool becomes lodged and cannot be passed without help. It is a recognised complication of long-term constipation and of habitually being unable to answer the urge to go. Because the stool is stuck, it can partly block the bowel and cause liquid stool from higher up to leak around it.

Causes and risk factors

Chronic constipation is the main pathway, along with a low-fibre diet and inadequate fluids, immobility or prolonged bed rest, and general frailty. Medicines that slow the bowel are important contributors — especially opioid painkillers, and also some others such as certain anticholinergics and iron — as are older age and neurological conditions that impair bowel function. Overusing laxatives over time, ignoring the urge, and painful anal conditions that make people avoid going can all play a part.

Symptoms

There is often an inability to pass stool, or only small amounts despite the urge, and a sense of fullness or blockage in the rectum. The key trap is overflow diarrhoea: watery or liquid stool leaks around the hard blockage, so the person appears to have diarrhoea or new leakage — this must not simply be treated as ordinary diarrhoea, because anti-diarrhoeal treatment can make impaction worse. There may be abdominal bloating and cramping, straining and small stools, and sometimes rectal discomfort or bleeding from straining. In older people, the signs can be less specific — reduced appetite, nausea, confusion, general unwellness or new incontinence.

Red flags

Severe abdominal pain, a swollen and distended, tender abdomen, vomiting, and not passing any stool or wind can mean bowel obstruction, a surgical emergency — seek urgent care, calling 995 or going to A&E. Vomiting of faecal-smelling material, a high fever, or a rigid abdomen is also an emergency, and significant rectal bleeding or increasing pain rather than relief needs urgent review. As a general rule, overflow leakage in someone with known constipation is a warning sign to seek assessment, not to self-treat as diarrhoea.

How it is assessed and treated

Assessment covers the history (bowel pattern, diet and fluids, mobility and medicines — especially opioids) plus an abdominal examination and a digital rectal examination, which usually confirms hard stool in the rectum; where obstruction or a higher blockage is suspected, an abdominal X-ray may be used, with blood tests if the person is unwell. A GP manages most cases, with a colorectal surgeon or emergency team involved if obstruction is suspected or specialist disimpaction is needed. Clearing the stuck stool (disimpaction) is done under medical guidance, typically using laxatives, suppositories or enemas and sometimes manual removal by a clinician — this guide gives no doses, and self-treating overflow with anti-diarrhoeals should be avoided. The cause is then addressed, including reviewing and adjusting constipating medicines with the doctor (for example pairing opioids with a bowel regimen). Surgery is rarely needed, only for complications such as complete obstruction.

Preventing recurrence

After the impaction is cleared, preventing it from returning is the priority, especially for those most at risk. Gradually increasing dietary fibre — fruit, vegetables and wholegrains, with a general adult target of about 25–30 g a day — along with adequate fluids and as much physical activity or mobility as possible, keeps stool soft and moving. A consistent bowel routine helps: responding promptly to the urge, allowing unhurried toilet time and using good positioning, with a maintenance laxative plan if your doctor advises one. For anyone on opioids or other constipating medicines, or who is frail or immobile, a planned bowel regimen agreed with the doctor is the most effective safeguard, and carers should watch for the vague signs in older people and act on new “diarrhoea” in a constipated person rather than treating it as a bug. Keeping a simple record of when the bowels last opened is a practical way for families and care staff to catch a building problem early, before it becomes an impaction.

When to see a doctor

See a doctor if constipation does not improve within about a week or is worsening, if you cannot pass stool, or if someone with chronic constipation develops new watery leakage (possible overflow). Severe abdominal pain, a swollen tender abdomen, vomiting, or an inability to pass stool or wind is a 995 or A&E emergency, and there should be a low threshold to seek help for older, frail, immobile or opioid-treated people.

Related colorectal & digestive topics

Sources

MedlinePlus — Fecal impaction: medlineplus.gov
NHS — Constipation: nhs.uk
HealthHub (Singapore) — Constipation: healthhub.sg

General information only. This guide is general information about a colorectal or anal condition and is not a diagnosis or personalised medical advice. See a doctor or colorectal surgeon for assessment. Do not assume rectal bleeding, an anal lump, a non-healing sore, or a change in your bowel habit is “just piles” — these must be checked to exclude bowel or anal cancer. Seek urgent care for a painful, spreading anal swelling with fever, or severe abdominal pain with vomiting and not passing stool or wind (possible obstruction); call 995 for a high fever with rapidly spreading redness or severe illness.

Faecal Impaction in Singapore: Stuck, Hard Stool