The essence of the problem, as previously reported, indicated that few complications of acute appendicitis occur as long as the infection is contained within the appendix, but once the invading bacteria have penetrated the peritoneal appendicular surface or have invaded the regional circulation, any one or more of a series of serious complications can develop. Thus, rightfully, emphasis has been placed upon early removal of the inflamed appendix before penetration has occurred as the best method of preventing complications. We have shown that early appendectomy is predicated on early diagnosis and that diagnostic delay is not limited to extremes of age. The diagnosis may be obscured by an accurate, although misleading, history of prior acute attacks, by precident acute disease, such as viral gastroenteritis and by unimpressive symptoms blunted by intercurrent chronic illness, such as diabetes mellitus. If the elements of periumbilical pain, anorexia, nausea or vomiting and the migration of pain to the right lower abdominal quadrant are contained within the clinical history, one must suspect transmural progression of acute appendicitis; frequent inpatient examinations will allow earliest diagnosis and, thereby, fewest perforations and their attendant serious complications. Misdiagnosis is common. Any patient observed for an ostensibly nonsurgical acute condition of the abdomen who fails to improve markedly during a brief course of appropriate specific or supportive therapy must be thoroughly re-evaluated as a potential surgical candidate. Despite the proliferation of accessible laboratory tests and imaging procedures, the early diagnosis of appendicitis rests upon the clinical skills of the physician. A high index of suspicion is crucial. As Doctor Warfield M. Firor, former senior surgeon commented: "Pain and tenderness at any point where the appendix can lie must raise the diagnostic possibility of appendicitis."