This plant is toxic for small children, dogs, cats, birds, and other small pets. Peace Lilies release oxalate crystals (small needle-like crystals.) When the plant is breached (chewed, nibbled, broken), those crystals become embedded in tissue that comes into contact. If ingested, the embedded crystals cause an intense painful/burning sensation in the mouth resulting in drooling, difficulty in swallowing, vomiting, and possible swelling.