The most common causative agent of secondary peritonitis is Escherichia coli. Acute diffuse peritonitis is a very serious clinical condition and can be categorized as primary acute diffuse peritonitis or secondary diffuse peritonitis depending on its primary cause. Primary acute diffuse peritonitis is usually seen in young women, and its common causative organism is hemolytic streptococcus; while secondary acute diffuse peritonitis is usually seen in the clinical perforation of the digestive tract, such as gastric perforation and acute suppurative appendicitis perforation caused by diffuse inflammation of the abdominal cavity, and the clinical manifestations are full abdominal pain, pressure pain, and even the emergence of the “plate-shaped abdomen. “. Since the common cause is perforation of the digestive tract, the fluid from the digestive tract enters the free peritoneal cavity, and the bacteria therein grow and multiply, the common causative organism is Escherichia coli.