A small amount of fluid in the abdominal cavity means that there is fluid in the abdominal cavity, but the amount of fluid is not large. There are many causes of fluid accumulation in the abdominal cavity, such as bacterial infection, most commonly acute appendicitis or acute cholecystitis, which need to be clarified by going to the hospital for blood tests, C-reactive protein, abdominal ultrasound and abdominal CT. Antibiotics are usually given for treatment, and some patients need to have their appendix removed or gallbladder removed. Some patients have perforation of the gastrointestinal tract, such as gastric perforation, duodenal perforation, colonic perforation, etc. In this case, it is necessary to actively improve the relevant examination, repair the perforation, or remove part of the stomach, or remove the intestinal canal, and then do intestinal anastomosis. There are also some patients who are caused by malignant tumors, and it is not excluded that the fluid in the abdominal cavity is caused by hypoproteinemia, these need to go to the hospital to improve the examination and clarify the cause.