Shifting dullness is a common clinical method to check for the presence of fluid in the abdominal cavity. The principle is that when more fluid accumulates in the abdominal cavity (about 1000ml or more), when the patient is percussed in the supine position, the fluid accumulates in the low part of the abdominal cavity due to gravity, and the intestinal tube containing gas floats on it, so the percussion shows a drum sound in the middle of the abdomen and a turbid sound on both sides of the abdomen. A positive mobile turbid sound indicates an accumulation of fluid in the abdomen. Starting from the umbilicus, the patient was asked to percuss to the left until a turbid sound appeared, and the percussion plate finger was not moved. The treatment of common peritoneal effusion is as follows: 1. Systemic supportive therapy give high protein, high calorie diet. Extracorporeal total intravenous nutrition and input of albumin can support for a period of time. 2, diuretic therapy can relieve the symptoms of abdominal distension. However, excessive diuresis can lead to dehydration and hypotension, low blood bait and electrolyte disorders, which need to be adjusted with attention. 3.Intra-abdominal chemotherapy selects different chemotherapy drugs according to the primary cancer, commonly used drugs are mitomycin, adriamycin, cisplatin. 4.In recent years, it is useful to inject 400mg/mL after pumping clean abdominal fluid, once a week, and inject dexamethasone 10mg at the same time, and treat for 2 weeks. Warm tip: please combine the specific medication with clinical, by the doctor face to face guidance shall prevail.