Recently I was asked to comment about a rash of e-mails floating around cyber-space concerning the toxicity to dogs of mulch made from crushed cocoa bean hulls. Cocoa mulch is by-product of cocoa production. The dark brown mulch is aesthetically and aromatically pleasing, giving the garden a rich, chocolately scent. Since theobromine, a naturally occurring compound in chocolate is toxic to dogs, the internet is now filled with cyber-legends of dogs eating cocoa mulch and keeling over dead.
According to an article published in the Journal of the American Veterinary Medical Association (JAVM June 1, 2006 p. 1644), cocoa bean husks can contain up to 2.98% theobromine. The JAVN article state “no reports of lethal toxicosis from ingesting this mulch have been filed with the ASPCA Poison Control Center this year (2006). In 2004 and 2005, 16 reports of single exposure to the mulch were received, none resulting in death.”
The ASPCA posts this comment regarding cocoa mulch on its website:
“Dogs consuming enough cocoa bean shell mulch could potentially develop signs similar to that of chocolate poisoning, including vomiting and diarrhea. In cases where very large amounts of mulch have been consumed, muscle tremors and other more serious neurological signs could occur. To date, the ASPCA Animal Poison Control Center has not received any cases involving animal deaths due to cocoa mulch ingestion. One key point to remember is that some dogs, particularly those with indiscriminate eating habits, can be attracted to any organic matter. Therefore, if you have a dog with such eating habits, it is important you do not leave him unsupervised or allow him into areas where such materials are being used.”
It should be noted that processed cocoa mulch may contain much lower concentrations and some manufacturers market cocoa mulch that is ‘Pet safe’. Consumers should look for products that are tested and certified theobromine free.
As always, I stand by my recommendation to use locally processed wood products such as ground hardwood bark and ground pine bark. Plants grow well in these mulches, which are typically among the most cost-effective and natural looking (to me, at least) mulches available, and they are renewable and help support your local economy.