A food fatal to dogs

My black labrador has enjoyed the odd grape or two over the years but I am led to believe they are poisonous to dogs. How has he survived?

Neil says: It is a most curious thing, isn’t it? All fruits of the Vitis species have been implicated in toxicity and death after their ingestion by dogs. Only five grapes can, on occasion, kill a 10kg canine, but, for most, the risk is greater the more is consumed. Others, as you say, seem able to eat them with impunity. We do not know why some individuals suffer kidney shutdown up to 72 hours after eating grapes, but they do. Red, green, seedless and seeded grapes have been involved, whether they are commercial or homegrown, organic or non-organic. Grape pressings from wineries and foods containing grapes, raisins, sultanas and currants have also proven to be lethal. Inducing vomiting as soon as possible after ingestion (and perhaps for up to six hours), would seem to be sensible and aggressive fluid therapy is advocated, though it is not clear that this is effective. I would not tempt fate. Remember also that onions, garlic, alcohol, chocolate, cocoa, macadamia nuts, fattening foods, and foods containing the sweetener xylitol can also be fatal to dogs.