Bowel obstructions that occur are commonly caused by ingestion of foreign bodies, but can also occur from fecal impaction, intestinal worms, and cancerous masses. Usually if the item is small enough it will just pass through but on the rare occasion a large item or even string is ingested it is essential to provide first aid as those items can cause serious damage to your pet. Make sure to monitor your pet for unusual behaviors to indicate they may have ingested something they shouldn't have.