Fibrous membrane encapsulation, also known as “abdominal callus”, was named in 1978 and is a relatively uncommon disease in abdominal surgery. It is characterized by a dense, grayish-white, tough, hard and thick fibrous membrane wrapped around all or part of the small intestine. Because of its different etiology, different clinical manifestations and inconsistent understanding, it has been reported as “small intestine cocoon encapsulation, congenital small intestine confinement, small intestine stage fiber encapsulation, intestinal obstruction with intra-peritoneal adhesions” and so on. The etiology of cocoon disease is unknown and may be related to the following factors: 1. secondary to some kind of intra-abdominal inflammatory disease Foo et al. suggested that the disease occurs mostly in females, often within 2 years of menarche, which may be caused by the reflux of menstrual blood through the fallopian tubes into the abdominal cavity, inducing subclinical primary peritonitis with fibrous exudative mechanization. sieck et al. hypothesized that the disease may be caused by the regional onset and the prevalence of adolescent females. The sequelae of peritonitis caused by retrograde infection with pathogens susceptible to genital tract invasion. However, these speculations have not been confirmed and do not explain the onset of the disease in male patients, and the intraperitoneal inter-intestinal adhesions found during surgery are also different from peritoneal adhesions caused by general infection. 2, congenital developmental abnormalities Most scholars believe that abdominal cocooning is due to congenital developmental abnormalities combined with acquired causative factors, on the grounds that the peritoneum is intact, smooth, and not adherent to the wall peritoneum, and that some peritoneal pathology confirms peritoneal structures with a high rate of intra-abdominal concomitant malformations (54.3%), often with large omental defects. It is speculated that this may be due to abnormal development of the greater omentum or a double-sleeve development of the small intestinal mesentery, and the cause of intraperitoneal adhesions may be related to acquired factors. Other scholars believe that abdominal cocooning is a congenital paraduodenal hernia or colonic mesenteric hernia. 3, drug effects Seng reported cases with a history of taking propranolol (Jinan) (80 mg/d), it is believed that propranolol-like β-blockers reduce the ratio of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) that control normal cell proliferation, leading to excessive collagen proliferation and abdominal fibrosis. 4, primary peritonitis Francis noted a high incidence of abdominal cocooning in patients with cirrhosis, nephritis, malignancy and heart failure with ascites, especially in patients with cirrhosis after LeVeen shunt. Rong-Hua Wang, on the other hand, reported a high incidence in patients with tuberculous peritonitis.