Yes, Jack-in-the-pulpit is toxic to dogs!
Dogs accidentally consuming the Jack-in-the-pulpit 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).
Jack-in-the-pulpit consumption is also toxic to Cats and Horses.
Toxic Principles Of Jack-in-the-pulpit: Insoluble calcium oxalates.
More Info About The Jack-in-the-pulpit Plant
Scientific Name: Arisaema triphyllum
Family: Araceae.
Also known as: Three-leaved indian turnip, Devil’s dear, Wake robin, Starch wort, Wild turnip, Dragon root, Bog onion, Pepper turnip, Brown dragon, Memory root.
The answer is based on information found on The American Society for the Prevention of Cruelty to Animals (ASPCA) website.