Inflammatory bowel disease includes both Crohn disease and ulcerative colitis. Pediatric-onset inflammatory bowel disease differs from adult inflammatory bowel disease in disease type, location, progression, and sex preponderance, and 20% to 30% of inflammatory bowel disease is diagnosed in childhood. Children are more likely than adults to present with extraintestinal manifestations of inflammatory bowel disease (with aphthous ulcers, joint involvement, and growth delay being the most common). Inflammatory bowel disease flares typically require treatment with intravenous steroids and inpatient admission. Acute emergencies include toxic megacolon, intestinal obstruction, and perforation. The use of steroids may obscure diagnosis of an underlying abdominal emergency by masking signs and symptoms. The emergency clinician must be cognizant of such complications and diagnostic challenges when evaluating inflammatory bowel disease.