This article appeared in Dr. Karen Becker's daily email newsletter, "Healthy Pets".
"Recently, a young Australian Shepherd sampled some AA batteries and wound up in the veterinary hospital. When a dog chews and punctures a battery, the alkaline material can seep out, causing damage to tissues in and around the mouth, the esophagus, and farther down the GI tract. Symptoms of possible alkaline battery toxicosis also include difficulty swallowing, vomiting, abdominal pain, increased body temperature, black tarry feces, and an elevated white blood cell count."
Always be sure that batteries of any kind are properly stored and disposed of as they can obviously be a major hazard to your dog if chewed.