What it means
Ascites is the accumulation of fluid in the peritoneal cavity, the space surrounding the abdominal organs. From the Greek askos, a wineskin.
Causes in rough order of frequency:
- Cirrhosis of the liver — by a considerable margin the commonest
- Cancer, particularly ovarian, bowel and pancreatic
- Heart failure
- Infection, including tuberculosis
It presents as progressive abdominal swelling, with clothes and belts becoming tight, and often breathlessness as the diaphragm is pushed upwards.
In practice
Detected on examination by "shifting dullness" and confirmed on ultrasound, which is sensitive to small volumes.
Paracentesis is the procedure of drawing off the fluid, both to analyse it and to relieve symptoms.
Why it matters
Ascites is never a normal finding and always requires investigation to establish the cause.
Ascites with fever or abdominal pain suggests spontaneous bacterial peritonitis, a serious infection of the fluid requiring emergency admission.
It is important not to mistake progressive abdominal swelling for weight gain — a distinction that delays diagnosis in ovarian cancer in particular.
Clinically reviewed by Dr Mohammad Zubair Khan, GMC 7563469
Last reviewed
August 30, 2026