Quick answer. Most adult constipation is caused by low fibre, inadequate fluids, or inactivity and improves with simple lifestyle changes. New constipation after age 50, or constipation with weight loss, rectal bleeding, or a change in stool calibre, needs prompt assessment to exclude bowel cancer.
Constipation usually means fewer than three bowel movements a week, or stools that are hard, dry, or difficult to pass. It is very common and often linked to diet, fluids, and activity levels.
This guide explains the common and serious causes, the red flags that need urgent attention, and which specialist to see if symptoms persist.
At a glance
| Cause or pattern | What it may suggest | Urgency |
|---|---|---|
| Low fibre, low fluid intake, or inactivity | Lifestyle-related constipation | Self-care; review with GP if persistent |
| Recurring constipation alternating with diarrhoea, bloating, cramps | Irritable bowel syndrome (IBS) | See a doctor for assessment |
| Recent change in bowel habit after starting a new medication | Medication side effect (e.g. opioids, iron, some antacids) | Discuss with your doctor or pharmacist |
| New constipation over age 50, with weight loss or rectal bleeding | Possible bowel cancer or other serious bowel disease | See a doctor promptly; colonoscopy may be needed |
| Severe pain, vomiting, no passage of stool or wind | Possible bowel obstruction | Seek urgent medical care |
Red flags: when to seek care urgently
See a doctor promptly, and seek emergency care (call 995 in Singapore) for severe symptoms, if you have any of these:
- New or persistent constipation starting after age 50
- Rectal bleeding or blood in the stool
- Unintentional weight loss
- A change in the shape or calibre of your stools (e.g. persistently thin or pencil-like)
- Severe abdominal pain, vomiting, or inability to pass stool or wind (possible bowel obstruction)
- A family history of bowel cancer with new bowel symptoms
These features can signal bowel cancer or obstruction and warrant a colonoscopy to investigate.
Common causes of constipation
Most cases are functional and relate to everyday factors:
- Diet: not enough fibre (fruit, vegetables, wholegrains) or fluids
- Inactivity: a sedentary lifestyle slows bowel transit
- Ignoring the urge: repeatedly delaying a bowel movement
- Irritable bowel syndrome (IBS): a common functional gut disorder
- Medications: opioids, some painkillers, iron supplements, certain antacids and blood pressure drugs
- Pregnancy and hormonal changes
Serious causes to exclude
Less commonly, constipation reflects an underlying medical condition that needs investigation:
- Bowel (colorectal) cancer – especially with red-flag symptoms
- Bowel obstruction or stricture
- Hypothyroidism (an underactive thyroid)
- Diabetes and other metabolic conditions
- Neurological conditions affecting bowel function
A doctor can arrange blood tests, imaging, or a colonoscopy where appropriate.
Self-care and prevention
For everyday constipation without red flags, these measures often help:
- Gradually increase dietary fibre with fruit, vegetables, and wholegrains
- Drink enough fluids through the day
- Stay physically active
- Respond promptly to the urge to go, and allow unhurried time in the toilet
- Ask a pharmacist or doctor before using laxatives long-term
See a doctor if simple measures do not help within a couple of weeks, or sooner if red flags appear.
Which specialist should you see?
Start with your GP, who can assess your symptoms and arrange initial tests. If constipation is persistent, unexplained, or accompanied by red flags such as bleeding or weight loss, you may be referred to a gastroenterologist for further evaluation and a colonoscopy.
You can find experienced gastroenterologists in Singapore through our directory.
What to expect at the appointment
Your doctor will ask how long the constipation has lasted, how often you open your bowels, and whether stools are hard, thin or difficult to pass. They will ask about diet, fluids, activity, medications and any red-flag symptoms such as bleeding, weight loss or a recent change in bowel habit. The examination may include feeling the abdomen and, where appropriate, an examination of the back passage. Depending on your age and symptoms, blood tests, a stool test or a colonoscopy may be arranged, particularly when bowel cancer or another serious cause needs to be excluded.
How to prepare
It helps to note how often you pass stools, what they look like, and how long the problem has been going on. List all your medications and supplements, as opioids, some painkillers, iron tablets, certain antacids and some blood pressure drugs commonly cause constipation. Mention any family history of bowel cancer and any new symptoms such as bleeding or weight loss, as these guide how thoroughly you are investigated.
Self-management at home
For everyday constipation without warning signs, simple measures usually work and are worth giving a fair trial. Increase fibre gradually using fruit, vegetables and wholegrains, as adding too much too quickly can cause bloating and wind. Drink enough fluid through the day and stay physically active, since both help keep the bowel moving. Do not ignore the urge to go, and allow unhurried time in the toilet; a footstool to raise the knees can make passing stool easier. If you need laxatives, ask a pharmacist or doctor which type is suitable, and avoid relying on stimulant laxatives long-term without advice.
Special situations
New constipation starting after age 50, or constipation with rectal bleeding, weight loss or a change in stool calibre, should be assessed promptly because it can occasionally signal bowel cancer. In Singapore, adults aged 50 and above are encouraged to join national bowel cancer screening; ask your GP or a Community Health Assist Scheme clinic about a faecal immunochemical (FIT) kit, and the Singapore Cancer Society also provides free FIT kits to eligible residents. During pregnancy, constipation is common; increasing fibre and fluids and discussing safe options with your doctor usually helps.
Common questions
How long should I try self-care before seeing a doctor?
If simple diet, fluid and activity changes do not help within a couple of weeks, see a doctor, or sooner if any red flag such as bleeding or weight loss appears.
Are laxatives safe to use regularly?
Occasional use is generally fine, but long-term use should be guided by a doctor or pharmacist, who can identify the cause and recommend the most suitable approach.
Related guides
- Best Gastroenterology Clinics in Singapore — our editorial shortlist
- gastroenterology clinics directory
- Bloating
- Leg pain on walking
- Night sweats
Sources
- HealthHub (Singapore) – Constipation
- NHS – Constipation
- Mayo Clinic – Constipation
- SingHealth – Colorectal Cancer
- National Cancer Centre Singapore (NCCS) – Colorectal Cancer
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