Ascites, the condition in which a collection of fluid is formed in the peritoneal cavity. Ascites may form part of a general dropsy or it may exist by itself. In the latter case it is due either to disease of the peritoneum (inflammation or morbid growth), or to obstruction to the portal circulation, the most common cause of which is cirrhosis of the liver (q.v.). Ascites may be simulated by several other conditions, from which it has to be distinguished by careful examination. The amount of fluid which collects may in extreme cases amount to several gallons; the pressure exerted in such a condition gives rise to numerous distressing symptoms, the most noteworthy of which is shortness of breath.