"He just reached up on the kitchen counter, grabbed the wash rag, and sucked that thing down like a Hoover!" said the owner of a big basset hound named Hugo, who was brought to the clinic where I work. Science will probably never be able to fathom why animals, especially dogs, occasionally eat objects that are not food. When a foreign object causes blockage of the intestine, however, it can be a life-threatening medical emergency.

Dogs are more likely than cats to swallow foreign objects, and they are not always very selective. Things that a dog might decide to swallow range from plastic action figures to batteries to wash rags. Cats usually prefer things like string, tinsel, and Easter grass.

The most common symptom of a blockage caused by a foreign object is vomiting. Dr. Sheila McCullough, a veterinarian at the University of Illinois Veterinary Teaching Hospital in Urbana, says, "Instead of vomiting once or twice, the animal may vomit ten times in a day. If the animal vomits every time it drinks water, this may indicate an intestinal blockage."

Dr. McCullough warns, "Unfortunately, the problem may not be that straightforward. Sometimes the object causes only a partial blockage, which means that some food and water will continue to move through the system." The object may also move but get stuck periodically, which means that the signs may not be consistent and vomiting may not occur every time the animal eats or drinks.

The object could be in the animal's intestine for a long time before it is discovered. Dr. McCullough says, "In my experience, the longest amount of time that an animal had a foreign object in its digestive system was 3 months!"

The main way to diagnose an obstruction is by taking radiographs (X-rays) of the animal's abdomen. Veterinarians look not only for the object itself but also for abnormal areas of gas in the intestine. Sometimes the object will not show up well on the radiograph, but if abnormal gas patterns are observed the veterinarian may give the animal barium, which is like a "white dye" that is given orally and coats everything in the stomach and intestine. An object coated with barium will appear white in radiographs.

Once a foreign object obstruction has been diagnosed, the foreign object may be removed by surgery or with an endoscope, an instrument with a tiny camera and grasping tool inserted into the body through the mouth without surgery. Sometimes a foreign object can damage the intestine, so a section of the intestine has to be removed. Sharp objects may perforate the intestine, causing further complications, and something like string can cause the intestine to bunch up like an accordion. If this occurs, friction can cause the string to cut into the intestine like a saw, making many small perforations that must be repaired by the surgeon. If the intestine has been perforated, fluid from the intestine may have leaked into the abdomen, which can cause a serious infection called septic peritonitis. Dr. McCullough says, "All of these possibilities make recovery time for an animal that has just had a foreign object removed quite variable."

The most important thing a pet owner can do to prevent this problem is to make sure that things that could be swallowed are kept out of reach of pets. Dr. McCullough says, "People go to great lengths to "child-proof" their homes. It would save people a lot of grief and money if they would 'pet proof" their homes as well."

If your pet starts vomiting, look around and think about what is in your house and what the pet could have eaten. Dr. McCullough's rule of thumb is, "If they can get in to it, they will!"

An obstruction of the digestive system does not occur every time an animal eats a foreign object, but when a blockage does occur, it is a medical emergency that requires immediate attention. If you think that your pet may have eaten something that has caused an obstruction, contact your local veterinarian immediately!