Bilious vomiting in a neonate = surgical emergency until malrotation with volvulus is excluded. Non‑bilious vomiting suggests obstruction proximal to ampulla of Vater (pyloric stenosis, GERD) or medical causes. Use age, bilious color, abdominal distension, and associated symptoms to narrow differential.
Select age (infant, child, adolescent), bilious vs non‑bilious, associated abdominal distension, fever, headache, or signs of increased ICP → tool generates focused differential (GERD, pyloric stenosis, malrotation, intussusception, appendicitis, cyclic vomiting, pregnancy, diabetic ketoacidosis, increased ICP) and suggests diagnostic studies and treatment.