The email forward shown below warns that Cocoa Mulch can be harmful to dogs and relates the story of a dog named Calypso who died after eating the product.
It is true that Cocoa Mulch can contain substances that can harm dogs if ingested in sufficient quantities. Cocoa Mulch is made from the shell of the cocoa bean and is a by-product of chocolate production. Since the mulch is organic in nature, works well, looks good and can give the garden a pleasant chocolaty smell, it is popular with home gardeners. However, cocoa mulch can contain theobromine and caffeine, which are chemicals called methylxanthines that can be harmful to dogs. Dogs that consume cocoa mulch can develop methylxanthine toxicosis, a condition that can result in symptoms similar to canine chocolate poisoning. According to an American Veterinary Medical Association article:
Vomiting and muscle tremors were the most common signs of toxicosis that occurred following ingestion. Anecdotal evidence suggests that the severity of clinical signs increased when larger amounts were ingested. Other signs were tachycardia, hyperactivity, and diarrhea.
One report, published in a 1984 Journal of American Veterinary Medical Association, notes:
A dog, which ingested a lethal quantity of garden mulch made from cacao bean shells, developed severe convulsions and died 17 hours later. Analysis of the stomach contents and the ingested cacao bean shells revealed the presence of lethal amounts of theobromine.
That said, deaths from cocoa mulch poisoning appear to be quite uncommon. Information in the AVMA article notes that there were no 2006 reports of lethal toxicosis due to cocoa mulch ingestion as of late April and, of the 16 mulch related reports fielded in 2004 and 2005, none were fatal.
While the claim that coca mulch can cause canine illness is factual, the particular incident described in the message is unsubstantiated. It seems that the authors of these types of warning messages often have an unfortunate tendency to embellish the core information with anecdotal stories of questionable veracity, perhaps in a misguided attempt to add a human element to their claims. The message does not provide any method of verifying if Calypso did actually die as a result of consuming cocoa mulch or even if she was a real dog. The previously mentioned AVMA article questions the truth of the claims in the message:
The story being circulated about a young dog named Calypso ingesting cocoa bean shell mulch may be true, Dr. Hansen said, but the cause of the dog’s death is “highly suspect.” The statement that she vomited a few times is consistent with such poisoning, but not the absence of other clinical signs until the next day, when the dog is said to have had a single seizure during her morning walk and died instantly.
“A big problem from the perspective of a toxicologist and a veterinary clinician is that if you have poisoning from methylxanthines, you get a progression of signs — vomiting, diarrhea, more vomiting, trembling, the heart rate kicks up, then it may progress to seizures if the dose is exceptionally high, with death being uncommon,” Dr. Hansen said. “A necropsy would have likely shown that Calypso had an underlying condition that caused her death.”
Also, it should be noted that the level of methylxanthines is not the same in all cocoa mulches. The AVMA article notes that current processing technology may result in lower chemical residues. There are a number of companies that distribute the product and at least one, Mirana, claims that its mulch contains no detectable amount of theobromine and is “Pet Safe”. Another claims to have sold millions of bags of cocoa mulch and never had a single report about a dog getting seriously ill from eating the product.
Nonetheless, although the truth of Calypso’s story may be somewhat questionable, dog owners should take heed of the message’s warning. If you have a dog, especially one that is not fussy about what it eats (not an uncommon characteristic among our canine friends), it would be wise to avoid the use of cocoa mulch, or at least keep a close eye on Rover’s garden forays.
