Unfortunately, the ZZ plant is poisonous to cats, dogs, and other pets you might have because it contains calcium oxalate crystals in all its parts. If your pets ingest some leaves or take a bite of the stems, they may experience a burning sensation around their mouth and spit it out, which won’t cause any serious damage. But if your pet does ingest the leaves, stems, or roots, they’ll experience excessive drooling, nausea, vomiting, diarrhea, swelling in the throat, dehydration, etc. Therefore, keep these plants in an elevated position or fence them in so pets can’t reach them.