Gardening Mulching Poisonous Plants

Cocoa Mulch Can Be Poisonous to Dogs

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Cocoa mulch: could it poison your pet? Photo: A Girl With Tea, Wikimedia Commons

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

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Puppies will chew on almost anything… and that could include cocoa mulch. Photo: Wikimedia Commons

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.

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Even if your dog seems uninterested by cocoa mulch (mine isn’t), it’s still best to keep the two apart. Illus.: Ciker-Free-Vector-Images

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.

This brand (Cocoa™ Mulch) claims to be “pet safe”. I can’t find it in my area.

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.20170905A A Girl With Tea, WC

Garden writer and blogger, author of 65 gardening books, lecturer and communicator, the Laidback Gardener, Larry Hodgson, passed away in October 2022. Known for his great generosity, his thoroughness and his sense of humor, he reached several generations of amateur and professional gardeners over his 40-year career. Thanks to his son, Mathieu Hodgson, and a team of contributors, will continue its mission of demystifying gardening and making it more accessible to all.

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