Principles of diagnosis in acute abdominal disease. Method of diagnosis: the history. Method of diagnosis: the examination of the patiente. Method of diagnosis: the grouping of symptoms and signs. Laboratory and radiological tests. Appendicitis. The differential diagnosis of appendicitis. Diverticulitis of the colon. Perforation of a gastric or duodenal ulcer. Acute pancreatitis. Cholecystitis and other causes of acute pain in the right upper quadrant of the abdomen. Acute abdominal lesions arising in the left hypochondrium. The colics. Acute intestinal obstruction. Intussusception and other causes of obstruction. The early diagnosis of strangulated and obstructed hernias. Acute abdominal symptoms due to vascular lesions. Acute abdominal symptoms in women. Early ectopic gestation. Acute abdominal disease with genitourinary symptoms. The diagnosis of acute peritonitis. The early diagnosis of abdominal injuries. The postoperative abdomen. The acute abdomen in the tropics. Diseases that may simulate the acute abdomen. Acute abdominal pain in the immunocompromised patient. Abdominal catastrophes when sensation is impaired.