Are laurel berries poisonous?

The Carolina cherry laurel, Prunus caroliniana, produces berries that are toxic to humans, dogs and livestock but safe for birds. English laurel, Prunus laurocerasus, and mountain laurel, Kalmia latifolia, are also toxic, and the latter is particularly dangerous to livestock.

Cherry laurel, English laurel and mountain laurel are all grown as ornamental shrubs or trees for their attractive foliage and flowers. All parts of these plants are toxic, although mountain laurel has been used in herbal medicine as an external treatment for skin diseases. Both Carolina cherry laurel and English laurel contain cyanide, while mountain laurel contains grayanotoxin, also called andromedotoxin, and arbutin.