Foreign Bodies in Dogs and Cats

What is a foreign body?

Pets have the unfortunate tendency to eat things they shouldn't, and we aren't talking about food. Toys, socks, rocks and other materials find their way into pet stomachs but when the foreign body is a string, the consequences are especially dire.

Animals like to play with things and play often involves chewing. Chewing leads to accidental swallowing and from there, a potential disaster may occur. Pets of any age will play with toys but it is generally the youngsters who get into trouble with foreign bodies.

Common objects, or foreign bodies, that are swallowed include:

  • Corn cobs
  • Balls
  • Socks and underwear
  • Rocks
  • Jewellery
  • Toys
  • Leashes and collars
  • Plastic bags (especially if there has been food inside)
  • Pieces of shoes
  • Coins (pennies are especially dangerous)
  • Sewing needles
  • Fish hooks
  • The list goes on

Often these objects will pass out the other end in a day or two, though it is possible for a small object to rattle around inside the stomach without passing for weeks. If the object does not pass and causes an obstruction or partial obstruction, surgery will be needed to remove it.

Prompt diagnosis allows for prompt removal of the foreign body before the bowel is badly damaged. In more advanced situations, sections of damaged bowel must be removed and in the worst possible scenario, the
intestine breaks open and spills bacteria and digested food throughout the abdomen. This latter possibility is associated with very high mortality and is to be avoided at all costs.

Symptoms of a Foreign Body

General Symptoms

The foreign body patient develops a poor appetite and vomiting fairly quickly. They soon show no particular interest in anything and become lethargic. Pain may be difficult to recognise. The sooner the patient is evaluated by the doctor, the better.

Types of Foreign Bodies

Linear Foreign Bodies

As if all this wasn't bad enough, there is an especially bad foreign body situation when the object is a string or similar linear structure.  Common linear foreign bodies might include string or yarn (especially for kittens) or a towel or cloth leash where the fabric has not been completely chewed through and long threads are exposed.

The Drawstring Effect

Imagine a drawstring bag or a pair of pants. Tie a knot in one end of the drawstring so that it cannot move and pull on the other end. The fabric wads up along the string channel. If the string is pulled hard enough and the knot still will not budge, the string will actually rip right through the string channel. This is what happens in the linear foreign body scenario. The foreign body lodges somewhere in the GI tract and will not move. The strings, however, dangle forward in the GI tract like a drawstring. The intestine attempts to move them forward but because the foreign body is lodged, the bowel ends up inching up the strings similar to the drawstring channel on the pants. This type of folding upon itself is called “plication” and is the hallmark of the linear foreign body. If the foreign body is not removed, the strings will cut through the intestine leading to life-threatening peritonitis.

Linear Stomach Foreign Bodies

The other area where linear foreign bodies lodge is the bottom (pylorus) of the stomach. The stomach has a large storage capacity but all of its contents must ultimately drain out of the pylorus. And if there is a foreign body located in the stomach it will cause chronic irritation and inability in the stomach,  to function properly, causing pets to become extremely unwell. 

Diagnosis of Foreign Body

In some instances the veterinarian may be able to palpate or feel the object in your pets intestinal tract.  Often though blood work, radiographs, and/or ultrasound will need to be performed to get a diagnosis. Some objects are visual on radiograph, others just show typical signs of obstruction including a looping or gap in the intestines or an abnormal structure that is 'out of place’.  In some instances, the veterinarian may recommend an exploratory surgery to look to see if there is any foreign objects in the intestinal tract.


Because of the dire consequences of not doing surgery when it is needed, it is often best to opt for surgery earlier rather than later. The patient will need to be re-hydrated from past vomiting and stabilised prior to surgery.

Most likely the foreign body will be obvious in the stomach and/or intestines and can be removed. If the bowel is damaged or even perforated, sections of bowel may require removal. After surgery, several days in the hospital may be needed for recovery. If there is going to be a problem with an intestinal incision, it is usually seen by the third day after surgery.

The linear foreign body surgery is generally considered a higher mortality situation than those of more simple foreign bodies. Your pet will be sent home with post operative medications and will need to go on strict rest and diet instructions.  Your veterinarian will go through these instructions with you upon discharge.