Butterfingers are high in sugar and calories, which can lead to obesity and other health problems in dogs. Additionally, Butterfingers contain chocolate, which is toxic to dogs. If your dog eats a Butterfinger, he could experience vomiting, diarrhea, and even seizures. So while Butterfingers may be a tasty treat for your dog, it's important to remember that they aren't good for him. Stick to healthier treats like carrots or apples instead.