Ahh, reminds me of a story of my former dog, Kelly. She was just a lab sized mutt of some kind.
Well, when I was living in Japan, a friend of my parents came to visit from England. Brought all sorts of chocolates and goodies. When we were all out and about, going to show her famous sights in our area, the dog got into the chocolate. It had been put on the counter, and she had NEVER been a counter surfer in her life before. I think she was about seven then. Anyway, we got home, and found she had eaten nearly all of a 5lb dark chocolate bar, leaving only one row uneaten. We assume she was too full to finish. To top it off, it was a Sunday, and the only veterinary clinic on the military base was closed on Sundays, and their voice mail said to call the base ER in case of emergencies. The ER doc just said to watch her for signs of toxicity such as muscle tremors, and that she will likely have diarrhea, and if things got serious (he knew my Mom 'cause she was a Navy nurse who worked there) to bring her into the ER. The dog did have diarrhea, but nothing worse, she just got to live outside for a warm spring day while her system purged itself.