A 50-year-old man presented at the emergency unit with abdominal pain in the right lower quadrant and dysuria. He described an increase in pain during micturition. After multiple examinations (CT-scan, MR-scan, ileocolonoscopy) were performed to no avail, a toothpick was detected in the terminal ileum during an ultrasound scan of the small intestine. Prompted elevation of intra-abdominal pressure led to migration of the radiolucent sharp foreign body into the wall of the urinary bladder, inducing pain. Median laparotomy revealed a two-sided perforation of the terminal ileum with ileosigmoidal fistula, which was induced by an ingested toothpick. The patient underwent en-bloc resection of the infectious tumor by segmental ileal resection and sigma resection. Anastomoses were performed as hand-sewn end-to-end ileoileostomy and end-to-end stapled colorectal anastomosis, respectively. Ingested foreign bodies and perforation of the gastrointestinal tract by foreign bodies are rare events but may cause serious gut injuries. The ingestion of foreign bodies should be kept in mind as an important differential diagnosis in patients with acute abdomen or chronic abdominal pain of unknown origin, especially in children. Abdominal ultrasound can be a useful diagnostic tool in identifying ingested foreign bodies.