This is further information on mulch:
The toxic potential of mulch varies, depending on its components. It’s important to understand that any type of organic material can be very attractive to some dogs, and could possibly pose some level of risk—whether it is for toxicity or obstruction of the gastrointestinal tract. This is particularly true with dogs who have indiscriminate eating habits or are left unsupervised for significant periods of time.
Mulch varieties such as pine, spruce, cedar and fir may contain essential oils and resins that, in addition to the risk for obstruction, may produce gastrointestinal irritation—including drooling, vomiting and loss of appetite. If ingested in large enough quantities, even minor central nervous system depression can result.
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