Approximately 80% to 90% of gastrointestinal foreign bodies  pass through the digestive tract without causing clinical complications or harm to the patient. However, the remaining 10% to 20% of cases require endoscopic intervention, and about 1% may necessitate surgical treatment. Recent studies indicate that intentional ingestions are more likely to result in the need for both endoscopic and surgical intervention. True foreign bodies and food impactions can lead to significant morbidity, with serious complications including bowel perforation or obstruction, which may even result in death.

Perforation and obstruction from GIFBs can happen in any part of the digestive tract, but they are more likely to occur in areas of narrowing, angulation, anatomical sphincters, or where previous surgeries have taken place. The pharynx is the first site where foreign bodies can become trapped and cause complications. In the hypopharynx, small sharp objects, such as fish bones and toothpicks, can lacerate the mucosa or become lodged.

Once a foreign body enters the esophagus, there are four areas of narrowing where food boluses and foreign objects are prone to getting stuck: the upper esophageal sphincter, the level of the aortic arch, the level of the mainstem bronchus, and the esophagogastric junction. These areas have a luminal narrowing of 23 mm or less. However, food and foreign bodies more frequently become lodged in the esophagus at sites of pathology, including rings, webs, or strictures. Multiple esophageal rings, often associated with eosinophilic esophagitis, are contributing to an increasing prevalence of esophageal food impaction in young adults. Similarly, esophageal motility disorders, such as distal esophageal spasm or achalasia, may also lead to food or foreign body impaction in the esophagus.

Among all areas of the gastrointestinal tract, esophageal foreign body and food impaction generally carry the highest risk of complications, with the incidence of adverse events being most significant in this region (such as perforation, abscess, pneumothorax, mediastinitis, fistula or cardiac tamponade)

Sharp or pointed objects may have a perforation rate as high as 35%. Large objects (>2.5 cm [1 inch] in diameter) are sometimes unable pass through the pylorus.  Long objects (>5 cm [2 inches]) such as pens, pencils, and eating utensils can have difficulty passing around the duodenal sweep, ligament of Treitz or ileocecal valve.   Interestingly, most objects, including sharp ones,  seldom cause damage once in the small intestine and colon, because the bowel  peristalsis protects itself thanks to through and axial flow.