Ascites is a term that describes an accumulation of large quantities of fluid in the peritoneal cavity. In the vernacular, this symptom is also called “abdominal dropsy”. In approx. eight out of ten cases, the cause of ascites is decreased liver function, for example caused by cirrhosis of the liver. But ascites can also be caused by reduced myocardial function, kidney diseases or cancer. For most patients, medication and a special diet are adequate to drain this fluid again. However, for several thousand of patients per year in Europe and the USA, this therapy no longer works. Per day, an affected patient can accumulate up to two liters of fluid in the abdomen. For many patients, this accumulation of fluid in the abdomen is a big bur-den, as hitherto the only way to remove the fluid was by means of regular tapping.