!!!   POISON   !!!

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Pet owners beware: This warning is for real!

It's mulching season, and this landscaping essential just can't catch a break. First came a Web-based rumour in spring 2006 that termite-infested mulch was being shipped out of the Hurricane Katrina-affected zone and into flower beds across America. That alert proved bogus.

Next to circulate was a fear-inducing e-mail alerting pet owners to the fact that fragrant cocoa mulch can kill dogs that eat it. But there is truth to the claim, according to the American Society for the Prevention of Cruelty to Animals (ASPCA). Some dogs are attracted by the mulch's chocolate aroma, and according to a warning from the ASPCA in 2003, "Eaten by a 50-pound dog, about 2 ounces of cocoa bean mulch may cause gastrointestinal upset; about 4.5 ounces, increased heart rate; about 5.3 ounces, seizures; and over 9 ounces, death."

Cocoa mulch is made from crushed cacao shells, which contain caffeine and theobromine, two compounds to which dogs are particularly sensitive. (These substances are also present in everyday comestibles like baker's chocolate, chocolate bars and candies, colas, and tea.) Depending on the size of the dog and the amount of cocoa mulch it ingests, symptoms can range from stomach upset to cardiac arrest. Dogs metabolize the compounds slowly, so symptoms may take hours or even days to manifest themselves. The ASPCA's advice: Avoid using cocoa mulch anywhere unsupervised dogs roam.

Other natural alternatives to cocoa mulch, like cedar chips and pine straw, are typically less toxic but still may contain resins and oils that trigger gastrointestinal disorders in pets that ingest them. And all mulches, including those made from recycled plastics (see our report, available to subscribers), pose a choking hazard, especially in pooches with less-than-discriminating palates.

If you suspect your dog has eaten cocoa mulch or any other toxic substance, immediately contact your veterinarian or the ASPCA's Animal Poison Control Center at 888-426-4435. The center, open 24/7 every day of the year, charges $55 per consultation. 

Drolet R, Arendt TD, Stowe CM.


If your dog likes to spend his summer grazing in your garden, his treat-seeking nose may lead him to one danger in particular: the sweet-smelling, but potentially harmful cocoa bean mulch. Made of cocoa bean shells and considered desirable for its eventual degradation into organic fertilizer, this gardener’s choice can be toxic to canines if eaten in large quantities—and some dogs have been known to eat amazing amounts! 

In 2007, the ASPCA Animal Poison Control Center (APCC) handled 26 cases of cocoa bean mulch ingestion—a third originating in California. “Dogs are attracted to the fertilizer’s sweet smell,” says Dr. Steven Hansen, ASPCA Veterinary Toxicologist and APCC Director, “but like chocolate, cocoa bean mulch can be too much for our canine companions.” 

Ingestion of large amounts of cocoa bean mulch, which contains residual amounts of theobromine—a methylxanthine found in chocolate and known to be toxic to dogs—may cause a variety of clinical signs. These typically start with vomiting, diarrhea and elevated heart rate, and if large amounts are consumed, they may progress to hyperactivity, muscle tremors and possibly other more serious neurological signs. 

Treatment includes administering medical-grade activated charcoal, bringing tremors under control, cardiac monitoring and preventing further exposure. 

“One key point to remember is that some dogs, particularly those with indiscriminate eating habits, can be attracted to any organic matter,” says Dana Farbman, APCC Senior Manager, Professional Communications. “Therefore, if you have a dog with such eating habits, it’s important that you don’t leave him unsupervised or allow him into areas where such materials are being used.” 

To avoid contact, pet parents should consider a non-toxic alternative, such as shredded pine, cedar or hemlock bark. These will keep your pooch—and your garden—healthy.



April 16, 2006 | 
Cocoa bean shells, a by-product of chocolate production, are sold as mulch for landscaping. Homeowners find cocoa mulch desirable because it degrades into an organic fertilizer and provides an attractive color and odor. Unprocessed beans, derived from the Theobroma cacao plant, contain 1-4% theobromine/0.07-0.36% caffeine whereas, cocoa bean mulch contains 0.19%-2.98% theobromine. Some dogs find the mulch attractive and eat small to large quantities. …

Dogs consuming cocoa bean mulch may develop methylxanthine toxicosis. Retrospective case data suggests clinical signs following ingestion include vomiting and muscle tremors. Although oral doses could not be quantitatively determined, clinical severity increased with increasing qualitative dose descriptions. Therefore, treatment should be directed at controlling clinical signs until recovery and preventing further exposure. Pet owners should avoid use of cocoa bean mulch in landscaping around dogs with indiscriminate eating habits.

from ASPCA.org

According to tables we’ve examined, cocoa mulch contains 300-1200 mg. of theobromine per ounce, making cocoa mulch one of the strongest concentrations of theobromine your pet will encounter in any chocolate product. Yet the question of the gravity of the risk presented by this type of gardening mulch remains a matter of debate. According to Hershey’s, “It is true that studies have shown that 50% of the dogs that eat Cocoa Mulch can suffer physical harm to a variety of degrees (depending on each individual dog). However, 98% of all dogs won’t eat it.”

Rather than gamble their dogs won’t be attracted to the mulch, responsible pet owners will probably prefer to choose another form of soil enhancement for their gardens.

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Retrospective study confirms potential risks to dogs.

In response to increasing reports of dogs consuming cocoa bean shell mulch fertilizer, a retrospective examination of case data collected from January 2002 to April 2003 was conducted by the ASPCA (American Society for the Prevention of Cruelty to Animals) Animal Poison Control Center. The study concluded that dogs consuming cocoa bean shell mulch fertilizer may become ill, exhibiting signs consistent with methylxanthine toxicosis, which is similar to those seen with chocolate poisonings. The data suggests the most common signs that occurred following ingestion were vomiting and muscle tremors. Although it was not possible to quantify exact oral dosage amounts, the severity of clinical signs did appear to increase with the larger amounts anecdotally reported. "Since the updated data confirms that dogs can exhibit certain clinical effects after consuming cocoa bean shell mulch fertilizer, the ASPCA advises pet owners that they should avoid using this fertilizer around unsupervised dogs, and dogs with indiscriminate eating habits," comments Dr. Steven Hansen, Senior Vice President of the ASPCA Animal Poison Control Center.

The retrospective study was presented at the September 2003 North American Congress of Clinical Toxicology. The study includes six cases of dogs ingesting cocoa bean shell mulch fertilizer that were received and managed by veterinarians at the ASPCA Animal Poison Control Center between January 2002 and April 2003. Of the total case data collected by the center, these six were selected for further study because the final outcome of the animal's condition was known. There was a clear observation and/or evidence of ingestion and the managing veterinarian assessed the animals' clinical signs as having a medium to high likelihood of being related to the cocoa bean shell mulch exposure. Within the selected cases, 50% reported vomiting, 33% involved muscle tremors (the amount ingested in these cases were described as "large" or "significant") and 17% had elevated heart rates, hyperactivity, or diarrhea. In 33% of the cases no clinical signs developed. California was the state from which more than half the cases were reported.

Cocoa bean shells are a by-product of chocolate production, and are frequently sold and used for landscaping by homeowners. Some dogs appear to find the mulch attractive and ingest varying amounts. In general, while unprocessed cocoa beans, which come from the Theobroma cacao plant, contain approximately 1-4% theobromine and 0.07-0.36% caffeine, the theobromine content of processed cocoa bean shell mulch reportedly ranges from 0.19-2.98%. Dogs are known to be very sensitive to these chemicals, called methylxanthines.

If a dog has eaten cocoa bean mulch fertilizer it is important to immediately contact a veterinarian or the ASPCA Animal Poison Control Center at (888) 426-4435. Treatment will depend on how much cocoa bean mulch a dog has eaten, when the mulch was eaten, and whether the dog is sick. Recommended care may include placing your dog under veterinary observation, inducing vomiting, and/or controlling a rapid heartbeat or seizures. The entire contents of the study on Cocoa Bean Mulch As A Cause Of Methylxanthine Toxicosis In Dogs can be found at: http://www.apcc.aspca.org/cocoabeanmulch.

Veterinary & Aquatic Services Department, Drs. Foster & Smith, Inc.
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:: Poisonous Plants :: Non-Poisonous Plants :: Poisoned! :: Foods to Avoid ::
:: Cocoa Mulch :: Chocolate :: Raisins & Grapes :: Related Links ::

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