Dangers of Common Dog Chews
Rawhides
Rawhide treats are everywhere and dogs do like them. But what many people don't know is that rawhide treats can be VERY dangerous to your dog! Salmonella bacteria is often present, especially if the rawhide comes from outside the US. They have also been found to contain arsenic compounds (used as a preservative), antibiotics (which can kill good bacteria in your dogs intestines), mercury vapor, chromium salts, lead solutions, formaldehyde, and insecticides! Health problems from rawhide chews can included sore throat, acute pancreatitis, choking, and intestinal blockage.
The cured hide is supposed to be digestible, but it breaks down far too slowly in the intestines, and swallowing too many pieces too quickly can easily lead to gastric irritation from the abundance of undigested materials. This will usually be accompanied by vomiting or diarrhea. Worse yet, some of the swallowed pieces may be only partially softened and still have hard, sharp edges and corners. This can lead to choking, esophageal lacerations, and gastrointestinal obstructions. In the case of the obstruction, surgery will most likely be necessary to remove the rawhide.
Cow Hooves
Cow hooves are even more dangerous than rawhides. They are hard enough that a dog can actually break a tooth on one. They can also be chewed up into sharp fragments which may cause a partial intestinal obstruction. Partial obstructions are often difficult to diagnose until the point at which the fragment is ready to perforate the wall of the bowel from pressure against the sharp edges. If perforation has occurred, the infection that ensues from leakage of intestinal contents can be fatal.
Pigs' Ears
Pigs' ears can cause GI upset if overeaten, similar to the situation with rawhides, although obstructions are less common because the ears are not usually shaped into solid chunks.
Greenies
Greenies have a tendency to break apart in large chunks. PWDs are "gulpers" and will down those large chunks. Because of that, there is definitely the possibility of a resulting esophageal or intestinal blockage. More then one person has claimed that a large piece of Greenie became lodged in their dog's throats. One woman states that by the time her vet found the obstruction, it had become "glued" to the esophageal wall. According to the report, the doctors had an extremely difficult time removing the green chunk, and the dog died from surgical complications. Even that aside, the primary ingredient of a Greenie is cellulose, and carnivores are not equipped with the enzymes to break down and digest cellulose.
Other
What to look for with other dog chew products:
Dog chews can be dangerous if they are too soft for your dog’s jaw strength, too small for your dog’s mouth, if they break into pieces that are too brittle and sharp or are made of long indigestible string or rope. Supervise your dog when he has the chew - watch to see if the toy is doing what it claims to do. Is it just tiny little pieces or is the dog taking off big chunks?