Cocoa Mulch can be toxic to pets  

 

 No question about it, chocolate and other products made from coca beans - e.g., cocoa mulch - contain substances toxic to certain animals, including both dogs and cats. And the main culprit is indeed theobromine, a caffeine-like chemical which acts as a mild diuretic and stimulant in human beings but is poisonous to animals less well equipped to metabolize it. Cocoa mulch, which consists mainly of cocoa bean shells, contains a much higher concentration of theobromine than chocolate processed for human consumption. Dogs are attracted to the scent and in documented cases have eaten the stuff, leading to vomiting, diarrhea, trembling, seizures and, in some instances, death (see symptom list). While it's equally toxic to cats, veterinarians say they are less likely to ingest cocoa products and therefore less at risk.
If you suspect your dog may have eaten cocoa mulch, or any other plant that may be dangerous the ASPCA recommends contacting your veterinarian immediately or calling the Animal Poison Control Center at 1-888-426-4435 for expert advice. For a full list of poisons plants visit www.dogpack.com/health/poisonplants.htm