Foreign bodies with a sharp edge which are accidentally swallowed are likely to become lodged in the stomach. An animal study was undertaken to determine the outcome of orthodontic anchorage screw ingestion. The radiographic findings of ten Mongolian dogs that ingested a total of 10 orthodontic anchorage screws and 10 reamers (both a screw and a reamer per dog) were evaluated. The study showed that all orthodontic anchorage screws and reamers reaching the stomach spontaneously passed, with the exception of two reamers. Further investigation of clinical cases might be necessary to determine whether the results of our animal study are in accordance with clinical findings.