The main difference between Crohn's disease and irritable bowel syndrome is that Crohn's disease is an organic disease, also known as segmental enteritis, whereas irritable bowel syndrome is a functional disorder. The primary symptoms of Crohn's disease include mucous stools and pus-blood stools, and patients may also experience chills and fever. Complications may include the formation of fistulas, leading to peritonitis in patients. Irritable bowel syndrome is a functional disorder, mainly characterized by symptoms such as abdominal pain, diarrhea, and constipation. The treatment for patients with irritable bowel syndrome primarily involves the use of medications to regulate the intestinal flora and to modulate the intestinal nerves.