Dr. Rachit Agrawal Gastroenterologist in Nagpur, Provides all types of Stomach pain Treatment in Nagpur, where an ascitic tap is a medical procedure where a needle is used to drain fluid that is trapped in an internal body cavity, most commonly the abdomen (belly). Fluid may have to be drained from the abdomen for different reasons, such as if the fluid is stretching the abdomen and causing pain; if the fluid is infected; or if a doctor needs to analyse the fluid in a laboratory for the presence of any disease.