With all the holiday foods, treats, gifts, guests and socializing dogs can be exposed to things that are harmful. Even the best trained dog may be offered something they shouldn't eat or find something that isn't good for them. If you suspect your dog has ingested something they shouldn't have, getting proper treatment as quickly as possible is essential.
In our area emergency vets are quite a bit of travel time as well as being very expensive. One year our curious puppy ate something she shouldn't have (and that we shouldn't have left out). Of course it was a Sunday and knowing the emergency vet was over an hour away we contacted the ASPCAs Poison Control number (888) 426-4435. For a fee (a fraction of the cost of an emergency vet visit) they were able to advise us what to do and we avoided that long, scary and expensive trip. I highly recommend keeping their information close at hand.
You can also find a list of harmful plants, foods and other products on their website, https://www.aspca.org/pet-care/animal-poison-control, in addition to their mobile app.