In response to increasing reports of dogs eating cocoa bean mulch, a retrospective case study was conducted to further define this unique phenomenon. Sixteen cases of cocoa mulch ingestion by dogs were managed between January 2002 and April 2003.
Of these, six cases were selected for analysis because the final outcome was known, there was evidence/obseration of ingestion, and the managing veterinarian assessed the causality relationship as medium or higher.
They concluded that dogs consuming cocoa bean mulch might develop methylxanthine toxicosis. Clinical signs shown in the case studies included vomiting and muscle tremors, but life-threatening signs were not reported. Pet owners should avoid use of cocoa bean mulch in landscaping and around unsupervised dogs.
The sweet-smelling mulch made from cocoa bean shells seems like an attractive option to many home gardeners.
Cocoa bean mulch deters slugs and snails, and gives your garden an appealing chocolaty hue and aroma. Unfortunately, however, it is attractive to some dogs and cats, which can be poisoned by eating the mulch.
Most people know it isn’t a good idea to feed dogs chocolate. However, you might not be aware that cocoa bean mulch has the same potentially toxic agents.
There have been a number of warning emails circulating the Internet over the past several years about the dangers of cocoa mulch for pets, and as always, it’s time to tease out fact from fiction.
Why Is Chocolate Dangerous?
Cocoa mulch, commonly sold by Target, Home Depot, and a number of garden supply stores, is made from the spent cocoa bean shells from chocolate production. Cocoa beans contain the stimulants caffeine and theobromine, which are methylxanthines, and these chemicals are toxic to animals.
In dogs, low doses of methylxanthines can cause gastrointestinal upset (vomiting, diarrhea, and/or abdominal pain) and muscle tremors.
However, if consumed in large quantities, cocoa mulch can be fatal to animals.
Higher doses can cause severe and even life-threatening symptoms such as rapid heart rate (tachycardia), seizures and death. According to animal poison control, the clinical severity of symptoms is dose dependent.
There has been at least one confirmed death of a dog after consuming cocoa mulch. Drolet reported that one dog, which had ingested a lethal quantity of cocoa bean mulch, developed severe convulsions and died 17 hours later. An analysis of stomach contents revealed the cocoa bean shells contained 0.46 percent theobromine.
The hidden hazard in this garden fertilizer is certainly not worth the risk to your pets!
Hershey, the maker of cocoa mulch, reports 98 percent of dogs have an aversion to the smell and won’t eat it. But since this statistic was reported by the manufacturer rather than an independent party, you should assume that it’s a conservative estimate, at best.
According to Dr. Larry Family of the Aqueduct Animal Hospital:
“Puppies are very curious animals. So they’re going to be attracted to various things around the yard, and the effect of eating cocoa mulch seems to be more severe in the small breeds, and it depends on the amount they actually ingest.”
How Much is Too Much?
According to the ASPCA, the following effects could be expected in a 50-pound dog that consumed varying amounts of theobromine and caffeine:
- If 100 mg of theobromine and caffeine were ingested, mild symptoms would occur.
- If 200-250 mg of theobromine and caffeine were ingested, severe symptoms would occur.
- If 300 mg were ingested, seizures would occur.
- For milk chocolate, less than 2 ounces per kg of body weight is potentially lethal to dogs; therefore, a 50-pound dog could potentially die from ingesting less than 100 ounces (6.25 pounds) of milk chocolate.
- For baking chocolate (unsweetened), less than 0.2 ounces per kg is potentially lethal to dogs; your 50-pound dog could die from eating less than 10 ounces of this very concentrated dark chocolate.
How does this translate to the amounts of cocoa mulch needed to make your dog ill?
The ASPCA has published a warning about cocoa bean mulch and dogs, in which they give the following estimates about how much cocoa bean mulch might be harmful. Keep in mind that these numbers are based on a retrospective study of only six cases. Therefore, these estimates should be taken only as loose guidelines:
- 2 ounces of cocoa bean mulch would likely cause gastrointestinal upset.
- 4.5 ounces of mulch would likely cause tachycardia.
- 5.3 ounces would likely result in seizures.
- 9 ounces or more would likely be lethal.
Why would consuming six pounds of milk chocolate be lethal for this 50-pound dog, when it would take only nine ounces of cocoa mulch to have the same lethality?
The answer is the shells of cocoa beans have much higher theobromine levels than the levels in milk chocolate. Unprocessed beans from the theobroma cacao plant contain 1-4 percent theobromine (600 mg/oz) and 0.07-0.36 percent caffeine. Cocoa bean mulch contains 0.19-2.98 percent theobromine (255 mg/oz).
Contrast that with milk chocolate, which contains only 58 mg/oz theobromine, and you can understand why it takes less mulch than milk chocolate to make your dog sick.
Recognizing Methylxanthine Toxicity, and What to Do About It
An animal will usually show clinical signs of toxicity about 6-12 hours after ingestion. Initial signs are excess thirst, vomiting, diarrhea, and restlessness. Symptoms progress to hyperactivity, excess urination, tremors and seizures, as well as other major cardiovascular and neurological signs. Death is generally due to cardiac arrhythmias or respiratory failure.
If you suspect your dog has eaten cocoa bean mulch, immediately contact your veterinarian or the ASPCA Animal Poison Control Center (1-888-426-4435).
Treatment of affected dogs includes administration of multiple dose activated charcoal (2 grams per kilogram of body weight), IV support, and tremor control with cardiac monitoring.
Treatment depends on how much of the mulch was eaten, when it was eaten, and whether your dog is sick, so the more information you can give to your veterinarian, the better.
The upside is that, with appropriate and timely treatment, most animals will make a full recovery.
In addition to the above, there are other potential medical concerns. Cocoa bean mulch has been found to contain pesticides and mycotoxin-producing mold, which causes other major health problems for animals.
I recommend avoiding the use of cocoa bean mulch, even though it smells wonderful … even if you don’t own pets. It might be just as toxic to your neighborhood wildlife and neighborhood pets that have indiscriminant eating habits.
Some manufacturers of cocoa mulch now proclaim that their products are organic, theobromine-free and pet safe, or contain only “trace amounts” of theobromine. It is difficult to verify these claims, so you would be better off choosing another form of soil enhancement, such as a cedar-based product, rather than gamble that your pet won’t be attracted to or harmed by the cocoa mulch.