Raisin & Grape Toxicity

There are many different toxins that can affect our pets.  Most of these toxins are also toxic to humans so we know to be careful with pet exposure.  However, some agents are toxic to pets while being non-toxic to humans, and it is these agents that are dangerous as most people do not know they are pet toxins.  The most common example of this is chocolate, as some forms are highly toxic to pets. 

A less known toxin for pets is raisins and grapes.  The ASPCA Poison Control Center indicates that raisins and grapes may be toxic to some dogs.  The ASPCA Poison Control Center managed 140 cases of raisin or grape toxicity in the last year.  Over 50 of these dogs developed symptoms ranging from vomiting to kidney failure, and 7 of these dogs died.  The toxic principal causing these symptoms has yet to be identified.  One specific case involved a 2 year old Australian shepherd that ingested 1 cup of raisins.  The dog developed acute kidney failure a few days later and died. 

Dose: First, we should look at the amounts of grapes or raisins that were ingested by these dogs. The bottom line is that the harmful amounts ingested were sometimes quite small. In one dog in the study, as well as in another dog of which I am aware, as little as 10 to 15 grapes resulted in acute kidney failure. These were both smaller dogs (Dachshunds). In other dogs, doses for grapes were as low as 0.3 oz/lb while doses for raisins were as low as 0.05 oz/lb. (Keep in mind that one raisin equals one dehydrated grape.)

Clinical Signs: Vomiting usually developed within 24 hours after ingestion, with signs such as lethargy, anorexia and, sometimes, diarrhea following soon after. Often grapes or swollen raisins were present in the vomitus or in the stool. More concerning was the kidneys stopped producing urine, which usually developed 3 to 5 days after exposure in half of the dogs. Other signs such as ataxia (wobbly) and weakness developed in roughly 20% of the dogs in the study over a similar period of time. Dogs that developed these signs were determined to be 12 to 18 times less likely to survive.

Xylitol Toxicity

Another toxin the ASPCA is cautioning owners about is xylitol.  Xylitol is a sweetener found in certain sugar-free chewing gums, sugar free jello pudding, candies, and other products.  According to the ASPCA veterinarians, dogs ingesting significant amounts of gums and candies containing xylitol may develop a sudden drop in blood glucose level resulting in depression, loss of consciousness, and seizures.  After known ingestion of this chemical, it is important to get your pet to a veterinarian immediately.  Xylitol can causes liver failure in dogs, the mechanism of toxicity is still not known. 

In humans, xylitol has little effect on blood insulin or blood sugar levels, but in dogs xylitol is a strong promoter of insulin release and can cause severe low blood sugar (hypoglycemia). Signs of collapse, ataxia (wobbly) and seizures are often seen. Low blood potassium may be present. In many dogs xylitol can cause liver necrosis and death. As little as 2 pieces of gum has resulted in low blood sugar in a 20lb dog!