The Hidden Dangers of Cocoa Mulch

It is a mistake every pet owner could easily make. As spring approaches, you head to the local home and garden store for mulch to freshen up your flower beds. Next to the bags of traditional shredded mulch are bags of a newer type—cocoa mulch.

According to National Cocoa Shell, the nation’s largest retailer of cocoa shell mulch, the material is leftover from the cocoa bean roasting process—making the product more environmentally friendly than regular mulch. Plus, who couldn’t resist putting chocolate smelling mulch down in their garden? For chocolate lovers across the country it’s a dream come true.

But there’s a catch. Cocoa mulch is extremely toxic to pets, especially when curious dogs have access to the outdoors.

Dr. Maureen McMichael is a veterinarian at the University of Illinois Veterinary Teaching Hospital in Urbana who specializes in emergency and critical care. She says, “Cocoa mulch is significantly more toxic than milk chocolate or even baker’s chocolate because it has quite a bit more theobromine in it.” Theobromine is the toxic compound in most chocolates that is responsible for the clinical signs seen in pets after ingestion.

Though it, too, can be deadly to pets, milk chocolate has only 44 mg. per ounce of theobromine. Baking chocolate has nearly eight times the concentration of theobromine in it compared to milk chocolate, making it one of the most toxic kinds of chocolate, but still not as concentrated as cocoa mulch.

In addition to having more theobromine in it, cocoa mulch is also usually found in an unlimited supply to the pet. Your Labrador may gobble up that chocolate bar on the counter, but left to their own devices, most dogs will eat cocoa mulch until you catch them or toxic effects start to set in, leading to the ingestion of large amounts of the toxin. “Unfortunately, many of the dogs that present with a history of eating cocoa mulch do not survive if they were not stopped quickly,” notes Dr. McMichael.

The clinical signs of chocolate or cocoa mulch toxicity include: hyperactivity, muscle tremors, fast heart rate, hyperthermia, and seizures. There are anecdotal reports from gardeners who unknowingly purchased the mulch and later found their dog dead after a very short exposure time. Incidents such as this are likely a result of heart arrhythmias that develop after ingestion.

After time, the sweet smell of the cocoa mulch will wear off, and some have questioned if, after that point, it is safe for dogs to be around it. Dr. McMichael cautions that, “it is possible that dogs are not attracted to it once the smell wears off but that does not eliminate its toxic load—it is still toxic.”

The moral of the story is: don’t purchase cocoa mulch if you have an outdoor pet. That said, if you happen to make the mistake of buying the mulch and you catch your animal eating a bite, time is of the essence. The quicker you can get Fido to the veterinary emergency clinic, the better the chances are of survival.

For more information on the topic, please contact your local veterinarian.

Ashley Mitek is an information specialist at University of Illinois’ College of Veterinary Medicine.