You know chocolate is toxic to dogs, but did you know cocoa mulch is too? It’s made from the shells of cocoa beans, and is a by-product of chocolate production. While cocoa mulch doesn’t contain as much theobromine as unprocessed cocoa beans – 0.19% to 2.98% versus 1% to 4%, according to the ASPCA Animal Poison Control Center — if enough mulch is ingested, it can have serious repercussions.

The Animal Poison Control Center conducted a study of dogs that accidentally ingested cocoa mulch. Vomiting was reported in 50% of cases, tremors occured in 33% and 15% of the dogs developed tachycardia. No clinical signs were seen in a third of the dogs, likely because they ate only small quantities of the mulch.

The Merck Veterinary Manual states that the median lethal dose of theobromine is 100 mg to 200 mg per kilogram of a dog’s body weight, but adds that serious symptoms and death can occur at much lower doses, and that individual dogs have varying sensitivities to the chemical. “In general,” the manual continues, “mild signs (vomiting, diarrhea, polydipsia) may be seen in dogs ingesting 20 mg/kg, cardiotoxic effects may be seen at 40 to 50 mg/kg, and seizures may occur at doses larger than 60 mg/kg.”

Even if none of your patients are indiscriminate eaters, it’s best to err on the side of caution and advise clients to avoid cocoa mulch and choose an alternative.