Contacting the vet is the first thing you need to do if your dog ingests toxic mice poison. Refrain from inducing vomiting in dogs unless it is as per the vet's instructions. Activated charcoal administration by mouth is also an ideal practice, as it prevents toxins absorption in the stomach.
However, if you use non-toxic baits, there's no need to worry. Such products are not harmful to pets or kids per contact, but if your child finds and eats such a bait, it is better to contact your doctor anyway.