Mulch varieties such as pine, spruce, cedar and fir may contain essential oils and resins that, in addition to the mulch's risk for obstruction, may produce gastrointestinal irritation (including drooling, vomiting and loss of appetite) and occasionally even minor central nervous system depression if ingested in large quantities. Dogs are especially attracted to cocoa bean shell mulch with its pleasant chocolate smell. Consuming large amounts can lead to signs similar to chocolate poisoning, including vomiting and diarrhea, and in cases where very large amounts have been consumed, muscle tremors or more serious neurologic or cardiac signs may occur.
Because your dog has demonstrated an attraction to mulch, he'll need to be supervised when spending time in mulched areas of your yard, and you may want to consider modifying his behavior to teach him not to eat mulch or other non-food items. Please consult our Virtual Behaviorist for tips about training your pup to stay away from toxic items.