Bloating and Abdominal Distension — What Causes It
Also described as gas, stomach fullness, abdominal distension, flatulence.
Bloating that varies through the day, settles overnight and comes with a change in bowel habit is usually functional, often irritable bowel syndrome or a food intolerance. Persistent bloating that does not fluctuate, especially in women over 50, needs assessment to exclude an ovarian cause.
🚨 Get emergency care if you have
- •Bloating that is persistent and does not settle overnight
- •Bloating with weight loss or loss of appetite
- •Bloating with abdominal or pelvic pain in a woman over 50
- •Difficulty eating or feeling full very quickly
- •Bloating with vomiting and absolute constipation
What causes bloating?
Irritable bowel syndrome
Bloating with cramping and altered bowel habit, worse through the day, better overnight.
Lactose or food intolerance
Bloating and wind within hours of specific foods, reproducible on re-exposure.
Constipation
Distension from a loaded bowel, relieved once the constipation is treated.
Ovarian cyst or mass
Persistent distension with pelvic discomfort and early fullness. Assessed with ultrasound and CA-125.
Small intestinal bacterial overgrowth
Bloating soon after meals, often following gut surgery or with slow transit.
How it is investigated
- ✓Abdominal and pelvic ultrasound
- ✓Coeliac screening and haemoglobin
- ✓Breath testing for lactose intolerance or bacterial overgrowth
- ✓CA-125 where an ovarian cause is being considered
Not every patient needs every test. The consultation decides which of these apply to you.
Frequently asked questions
When is bloating serious?▼
When it is constant rather than fluctuating, does not settle overnight, or comes with weight loss, early fullness or pelvic pain — particularly in women over 50, where persistent bloating is one of the recognised presentations of ovarian cancer and is worth an ultrasound.
Which foods commonly cause bloating?▼
Lactose in dairy, wheat, beans and pulses, onion and garlic, cabbage family vegetables, artificial sweeteners ending in -ol, and fizzy drinks. A structured elimination and reintroduction under dietitian guidance identifies triggers more reliably than cutting out foods indefinitely.
This page is general health information, not a diagnosis or a substitute for a consultation. Symptoms overlap between harmless and serious conditions, and only an examination can tell them apart. If you are worried, see a doctor.
Plan your first visit
Not sure which specialist to see? Tell our care team the reason for your visit and we will help you choose.
- Bring previous prescriptions, relevant test reports or scan images, a medication list and photo ID.
- If you plan to use insurance, bring your policy details. OPD, tests and admission benefits depend on your individual plan and approval.
- Your first consultation determines which tests or treatments are needed; not everyone needs every test listed on this page.
Appointments are requests until confirmed. In a medical emergency, call 044 2025 2025 or go to the nearest emergency department.