The Pennsylvania Veterinary Medical Association said many pets find the constant commotion of ringing doorbells and lots of strangers coming to the door frightening and may bolt when the door is open.
"Make sure your pet is wearing a collar with contact information for you or your veterinarian. Also, if your pet is microchipped, make sure your registration information is up-to-date," the veterinary association said in a statement. "The microchip won't do any good if you can't be reached."
Be sure to keep candy out of reach of dogs while waiting for or talking to trick-or-treaters. Chocolate is poisonous to dogs, and depending on the size of the dog and the strength of the chocolate, it can cause death, the veterinarians said.
In 2010, the Pet Poison Helpline said chocolate consumption among dogs increased more than 200 percent.
"If your dog has gotten into the chocolate candy, call your veterinarian or the Pet Poison Helpline immediately. The chemical toxicity results in vomiting, diarrhea, hyperactivity, inflammation of the pancreas, an abnormal heart rhythm, seizures and, sometimes, even death," the veterinarians said. "In smaller dogs, even the wrappers from candy can result in a secondary obstruction in the stomach or intestines."
If you have any suspicions about what your dog has ingested, be sure to consult your veterinarian immediately or contact The Pet Poison Helpline at 1-800-213-6680 or www.petpoisonhelpline.com.