Beware of two types of mulch that can be harmful to your pet. Cocoa mulch, produced as a byproduct of the food industry, has become increasingly popular with home gardeners for its sweet scent and fine-textured appearance. Unfortunately, it contains the same toxic compounds found in processed chocolate and can be deadly if ingested by your dog. Coconut husks have also become a popular mulch option. Green enthusiasts are quick to spread the coconut-husk mulch - known for its ability to soak up and retain many times its weight in water - around thirsty plants. However, it will quickly swell in the digestive tract of any dog that consumes it and potentially cause blockage of the intestines. (Information from - Dogscaping: Creating the Perfect Backyard and Garden for You and Your Dog by Thomas Barthel)
Other natural alternatives to cocoa mulch, like cedar chips and pine straw, are typically less toxic but still may contain resins and oils that trigger gastrointestinal disorders in pets that ingest them. And all mulches, including those made from recycled plastics, pose a choking hazard, especially in pooches with less than discriminating palates. If you suspect your dog has eaten cocoa mulch or any other toxic substance, immediately contact your veterinarian or the ASPCA's Animal Poison Control Center at 888-426-4435. The center, open 24/7 every day of the year, charges per consultation apply.