The first time I heard that cocoa mulch could be toxic to dogs, I was sure it was a garden myth, an urban legend. Especially since I was using it in my own garden … and I own a dog. How can such an innocuous product be toxic to family pets? But it seems that it’s true … at least a bit.
Delicious to People, Toxic to Pets
Cocoa beans, harvested from the tropical cocoa tree (Theobroma cacao), contain theobromine, a product related to caffeine that humans assimilate very well, but that dogs and cats can’t metabolize. Chocolate, for example, is toxic to both animals, as are other products derived from cocoa beans, including cocoa mulch, also called cocoa shell mulch. It’s made of cocoa bean hulls, a by-product of chocolate production.
Even so, cocoa mulch has been used extensively used in landscaping, even in public parks, for decades and there seems little mention of actual poisoning in dogs or cats. Why not?
Not Attractive to Animals
It turns out that dogs simply aren’t very interested in cocoa mulch. Even though humans find that cocoa mulch feels deliciously good (it really does smell like chocolate, at least the first few weeks after its application!), dogs seem indifferent to the odor or even repelled by it. That’s why they so rarely ingest any. The risk is greatest in puppies, ready to chew on almost anything. Most cases of poisoning from cocoa mulch are relatively minor, but some dogs eat enough to become very sick and there is even one case of a fatality.
In cats, despite the potential toxicity of cocoa hulls, the risk of poisoning seems almost nil. They simply have no affinity for cocoa mulch and don’t ingest it. To my knowledge, there has never been a case of poisoning following feline ingestion of cocoa mulch.
Despite the relatively small risk from cocoa mulch and the presence of all sorts of other much more poisonous things in the average pet’s environment (even seemly innocuous things like onions and grapes can be deadly to dogs and cats!), I suggest dog owners avoid using cocoa mulch. If it’s too late and the mulch is already installed, keep an eye on your pet. Remember, cocoa mulch biodegrades quite rapidly, usually within 10 to 14 months, so the danger decreases over time.
Also, keep your dog under control when you take him on a walk, because there may be cocoa mulch in other people’s gardens. Even a few hulls ingested can cause vomiting.
There are also, apparently, detoxified brands of cocoa mulch where theobromine has been destroyed by heat treatment. They’ll be labeled “pet safe” or “pet friendly.” Dog and cat owners can use those safely where they are available (I haven’t seen them in my neck of the woods).
In Case of Poisoning
If you suspect your dog has consumed cocoa hulls (symptoms include vomiting, diarrhea, increased thirst, panting, restlessness, excessive urination and an accelerated heart rate), induce vomiting and get him to the vet immediately. It is rare for a dog to ingest a lethal amount of cocoa mulch, but it can still get very sick and will certainly need treatment.