Chocolate - I think it can also very much depend on the dog involved. We had a nice lab mix come in a few days ago who hopped a baby gate to get to the tree and the gifts under it, and the 18 oz chocolate box with the rest of the gifts. Dog vomited once at home, and again at work with us, after we gave her an emetic. Vomited SO copiously it was amazing... She felt better after that, but her bp went up and her heart rate went up, and she was pretty dehydrated. They took her home again when we closed (no overnights) and I'd guess they gave her fluids of some kind at home, because when she came back the next morning I'm told she was in good shape, no longer at risk.
$500 bill for the owner to find out that chocolate under the tree is highly attractive and easy to get to for a 60 lb. dog, baby gate or no baby gate. And she snaked the box out of its gift bag without damaging the bag, and then peeled open the box just tearing a small spot on the hinge of the box! I've seen people who couldn't do such a tidy job of opening that!! Sweet dog, I'm glad she's OK.