Many owners will, on occasion, share a small tidbit of human food with their canine companions. But it's important to make sure that you are aware of what foods are safe, and which ones can potentially be dangerous. Grapes and raisins are toxic to dogs, and at certain concentrations can even be fatal.
It's not yet know exactly what in the grapes is toxic to dogs. There have been cases where dogs were poisoned after eating grapes or raisins, and in some instances the fruits have proven fatal. The dogs ultimately experienced kidney failure, but first display classic signs of poisoning such as acting lethargic, vomiting, and diarrhea. These symptoms may start as soon as a few hours after your dog eats grapes or raisins. More advanced symptoms can include food refusal, abdominal pain, and increased thirst. Severe symptoms can sometimes take as long as 24 to 48 hours to appear.
The toxic dose of grapes is not well established, but the ASPCA Animal Poison Control Center suggests that a dose of 0.1 oz/kg can be toxic. Around 12 to 15 grapes can be deadly to a 15lb dog. Raisins are even more concentrated than grapes, making ingesting fewer of them dangerous.
If you regularly share your food with your dogs make sure to always check the ingredients first. The other day Kit kept trying to lick fruit juice out of my cup. Not really a huge deal, but I wanted to check the ingredient list before letting him have a taste. I was more looking to see if it had a lot of sugar or the potentially deadly (to pets) sugar substitute xylitol. While that wasn't the case, I did notice that the juice contained grapes. I'm glad I checked. A few licks of juice probably wouldn't have been enough to cause major issues, but it's better to be safe than sorry. I enjoyed the juice and gave Kit a more appropriate treat.
If your dog experiences any symptoms of poisoning, or you suspect your dog may have eaten either grapes or raisins, it's important to call your vet. The sooner the problem is dealt with, the more likely you are to avoid damaging your pets delicate kidneys.