SOMETIMES people buy cocoa-bean hulls from organic nurseries to use as mulch, not knowing that they are poisonous to dogs.
Dogs have died not only from eating cocoa-bean hulls, but also from eating chocolate in any form. The culprit is a caffeine-related chemical in cocoa called theobromine.
The effects of theobromine on both dogs and humans are similar to those of caffeine, and include anxiety, heart arrhythmias and gastrointestinal upsets. But dogs are less able than humans to eliminate the compound from their system, so they can be poisoned by much smaller doses.
The number of chocolate poisonings in dogs always increases around holidays, when there is more chocolate around for dogs to get into.
Dogs poisoned by theobromine may be anxious and agitated, with vomiting or diarrhea, rapid heart rate, tremors or seizures.
The most deadly effect of the chemical is heart arrhythmia, which is most dangerous for older dogs that may already have heart problems. There is no antidote, but vets can do a variety of things to stabilise the dog's heart and help clear the theobrominefrom its system.
Dogs can also be poisoned by caffeine, but such cases are rare, since a dog is less likely to gorge on coffee than on chocolate.