Maybe those antacid commercials in which people's stomachs expand like balloons make you giggle, but if your senior dog's stomach exhibits similar behavior, it's no laughing matter. It's a matter of life or death -- literally. If your dog's belly expands so much over a one-day period that it looks like someone pumped it full of air, you need to get him immediate attention. If he has this symptom, your dog often also becomes so restless that he can't get comfortable lying down. He may try to vomit.

The most likely cause of these symptoms -- particularly if your dog is a large, deep-chested animal, like a Rottweiler or Great Dane -- is gastric dilation, more commonly known as bloat. Other possible causes of expanding stomachs include rupture of an internal abscess and leakage of blood or lymph fluid into the abdominal cavity.

In any case, though, you need to get prompt veterinary attention to save your dog's life. Don't stop to call the vet to tell him that you're on your way — just get there. If the problem occurs after normal business hours, high-tail it to your closest emergency veterinary clinic.