The main concern of this chapter is to present acute abdominal pain. Abdominal discomfort is a common complaint stemming from a wide variety of causes. Although usually arising from the viscera or the parietal peritoneum, it may also result from referred pain or an intrathoracic disease process. This makes the differential diagnosis difficult and extensive. A complete history is important to rule out both systemic and extra-abdominal diseases such as diabetes mellitus, uremia, porphyria, sickle cell crisis, black widow spider bite, lead poisoning, trauma, acute myocardial infarction, pulmonary embolism, etc. A complete physical examination is essential. Vital signs may suggest sepsis (fever, tachycardia, and hypotension). Clinical testing may require blood and urine sampling as well as radiography. If surgery is required, infiltration of a local anesthetic by the surgeon or anesthetist at the end of the procedure is an effective alternative, especially in outpatients. Body wall somatic blocks can also be considered, including intercostal/subcostal, transversus abdominis plane (TAP), ilioinguinal/iliohypogastric, and rectus sheath blocks; however, these will only treat pain of the body wall and not visceral pain.