Cocoa Mulch, which is sold by Hardware Stores, Garden Supply and Landscaping supply stores, contains a lethal ingredient called "Theobromine". Theobromine is the ingredient that is used to make all chocolate — especially dark or baker's chocolate — which is toxic to dogs. Cocoa bean shells contain potentially toxic quantities of theobromine, a xanthine compound similar in effects to caffeine and theophylline.

According to the ASPCA:

"Cocoa beans contain the stimulants caffeine and theobromine. Dogs are highly sensitive to these chemicals, called methylxanthines. In dogs, low doses of methylxanthine 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, 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.)"

Cocoa Mulch is potentially lethal to dogs since it smells like chocolate and will possibly attract them to eat it. If it is ingested they can become very ill and possibly die. It is probably safest to choose another form of mulch than to take the risk that your much loved pet might be attracted to Cocoa Mulch.

For further information, please visit the following link to read the warning issued by the ASPCA:

ASPCA Animal Poison Control Center Issues Cocoa Bean Fertilizer Warning