Acute paralytic ileus is a condition where the intestine loses peristalsis without mechanical obstruction. It is commonly seen in hospitalized patients after abdominal surgery, severe medical illness, or medications affecting intestinal motility like opioids. Clinically, it presents with diffuse abdominal discomfort, nausea, vomiting, and distended abdomen with diminished or absent bowel sounds. Treatment involves treating the underlying cause, restricting oral intake, using nasogastric suction if needed, and parenteral fluids and electrolytes. Alvimopan may help reverse opioid-induced ileus.