Yes, Iris is toxic to dogs!
Dogs accidentally consuming the Iris plants can show the following clinical symptoms: Vomiting, Prolonged Depression, Incoordination, Hypersalivaton, Sleepiness Or Excitation, Dilated Pupils, Low Body Temperature, Low Blood Pressure, Coma, Seizure And Death (In Rare Cases).
Iris consumption is also toxic to Cats and Horses.
Toxic Principles Of Iris: Pentacylic terpenoids (zeorin, missourin and missouriensin).
More Info About The Iris Plant
Scientific Name: Iris species
Family: Iridaceae.
Also known as: Flag, Snake Lily, Water Flag.
The answer is based on information found on The American Society for the Prevention of Cruelty to Animals (ASPCA) website.
