Sold at Target and at some garden supply stores, cocoa mulch contains theobromine and caffeine (which apparently are present in virtually all chocolate, but higher, more toxic concentrations are found in dar chocolate). According to the ASPCA, “dogs are highly sensitive to these chemicals (called methylxanthines). Low doses can cause mild gastrointestinal upset (vomiting, diarrhea, and/or abdominal pain); higher doses can cause rapid heart rate, muscle tremors, seizures and death.”
“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 can cause death. (In contrast, a 50 pound dog can eat up to about 7.5 ounces of milk chocolate without gastrointestinal upset, and up to about a pound of milk chocolate without increased heart rate” – not that your dog should consume milk chocolate either!)
Some manufacturers of cocoa mulch proclaim that their products are theobromine-free and pet-safe, so be sure to check labels, OR choose another mulch form, such as a cedar-based product.
Clarification of an email making its way around the net can be found here:
Additional information on this topic from the ASPCA can be found at these links: