Raisins — Food safety facts
Do not feed · Dogs · full breakdown on the linked food page
Toxic, like grapes — a small amount can cause acute kidney failure. Even one raisin for a small dog deserves a vet call.
Short answer
Yes, this is urgent and you should call your vet or the ASPCA Poison Helpline now. Raisins are toxic to dogs and can cause acute kidney failure even in tiny amounts. A single raisin can be enough for a small dog, so monitor for vomiting, lethargy, or lack of appetite. Get professional help right away; early treatment improves the outcome.