We have learned, through trial and error unfortunately, that we cannot put presents under the tree, no matter how pretty it looks. They stay in a closed room until Christmas morning. I think the turning point was the year we came home to an empty box of fudge and coffee and tea spread all over and ground into the carpet. Oh! And it doesn't have to be food! There was the year that the lab ate bath products, including a cocoa butter based massage bar with glitter in it. I had to give her hydrogen peroxide to induce vomiting. At least the vomit smelled nice and was sparkly.
(I have had to call the Vet ER so many times to see if they've poisoned themselves, I should have it on speed dial)