Although Meckel's diverticulum is the most prevalent congenital abnormality of the gastrointestinal tract, it is often difficult to diagnose. It may remain completely asymptomatic, or it may mimic such disorders as Crohn's disease, appendicitis and peptic ulcer disease. Ectopic tissue, found in approximately 50 percent of cases, consists of gastric tissue in 60 to 85 percent of cases and pancreatic tissue in 5 to 16 percent. The diagnosis of Meckel's diverticulum should be considered in patients with unexplained abdominal pain, nausea and vomiting, or intestinal bleeding. Major complications include bleeding, obstruction, intussusception, diverticulitis and perforation. The most useful method of diagnosis is with a technetium-99m pertechnetate scan, which is dependent on uptake of the isotope in heterotopic tissue. Management is by surgical resection.