We report a case of a 36-year-old man who was admitted to the Emergency Department with right flank pain. The clinical presentation was suggestive of renal colic. However, a computed tomography scan showed the presence of a foreign body in the inferior duodenal flexure. Upper gastrointestinal endoscopy demonstrated a 6.5-cm wooden toothpick deeply embedded in the duodenal wall; this was removed via endoscopy. The peri-duodenal inflammatory reaction had encased the right ureter, resulting in hydronephrosis. The patient did well and was discharged on post-operative day 7. He did not recall toothpick ingestion. When evaluating patients with acute abdominal pain, foreign body ingestion should be considered. In patients with a history of toothpick ingestion, immediate diagnosis with endoscopic management should be performed.