Bloat, or gastric dilatation and volvulus, is a condition in which the stomach rotates on its own axis. Once the stomach flips, the entrance and exits to the stomach become pinched off, and it becomes greatly distended with gas that has no outlet. The stomach becomes greatly dilated and painful, and circulation to the stomach and other major organs becomes severely compromised, leading to shock and eventual death.

Bloat can occur rapidly; a dog can be dead within hours of the stomach distention. Bloat is most prevalent in large breeds with deep chests and seems to occur more commonly in dogs who have a tendency to be easily agitated or nervous, and in dogs who exercise after a large meal. Any time bloat occurs, it is very serious. Symptoms include attempts at vomiting with no production (occasionally they may get up small amounts of foamy fluid); a hard, distended abdomen; and severe abdominal pain. If you observe any of these symptoms in your dog, it must be transported to a veterinarian immediately. This is a true emergency.