note: this warning is a couple years old, but the first time I saw it was today . . . though it might be of interest to other dog owners . . .http://web.archive.org/web/20031013173740/http://www.aspca.org/site/News2?page=NewsArticle&id=12729(URBANA, IL) March 13, 2003 -- As spring approaches, people will start to tend their lawns and gardens. Many will consider using cocoa bean mulch as a fertilizer. Made from spent cocoa beans used in chocolate production, cocoa bean mulch is organic, deters slugs and snails, and gives a garden an appealing chocolate smell. However, it also attracts dogs, who can easily be poisoned by eating the mulch.
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.)
If you suspect that your dog has eaten cocoa bean mulch, immediately contact your veterinarian or the ASPCA Animal Poison Control Center (1-888-426-4435). Treatment will depend on how much cocoa bean mulch your dog has eaten, when the mulch was eaten, and whether your dog is sick. Recommended care may include placing your dog under veterinary observation, inducing vomiting, and/or controlling a rapid heart beat or seizures.
http://web.archive.org/web/20031013173740/http://www.aspca.org/site/News2?page=NewsArticle&id=12729also confirmed by snopes.com . . .
http://www.snopes.com:80/critters/crusader/cocoamulch.asp