Grape, Raisin, and Currant Poisoning in Dogs - VCA Animal Hospitals.
Why Are Raisins Bad for Dogs? Grape and raisin toxicity in dogs can cause serious kidney damage that can lead to acute (sudden) kidney failure, which can be fatal.

Why are grapes and raisins bad for dogs? eaten a grape.

This particular example perfectly highlights why Safety Concerns For Dogs With Raisin Grape Sensitivity is so captivating.
Grape or raisin ingestion is confirmed, even with no symptoms. Your dog is vomiting repeatedly or has bloody diarrhea. Urination has stopped or dramatically decreased.

This particular example perfectly highlights why Safety Concerns For Dogs With Raisin Grape Sensitivity is so captivating.
The toxic dose varies from dog to dog, but in some cases, can be very small (i.e. some dogs dont have to eat much of the fruit to become poorly). Treatment should be given quickly because left untreated, grape/raisin/currant/sultana poisoning can cause death.
When dogs eat grapes or raisins, almost 50% get kidney failure. The prognosis is decent if a dog just had a few grapes or raisins (depending on the dogs size) and received prompt treatment. The prognosis is bad if the kidneys stop functioning and no urine is generated.
Dog grape toxicity calculator. Did your dog eat grapes? Type in their weight and how many.Cornell's documented threshold of concern: more than 1 grape or raisin per 10 lb of body weight. The same per-piece threshold applies to both forms. No safe dose has been established.