Yes, European Bittersweet is toxic to dogs!
Dogs accidentally consuming the European Bittersweet 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).
European Bittersweet consumption is also toxic to Cats and Horses.
Toxic Principles Of European Bittersweet: Solanine.
More Info About The European Bittersweet Plant
Scientific Name: Solanum dulcamara
Family: Solanaceae.
Also known as: Climbing Nightshade, Deadly Nightshade.
The answer is based on information found on The American Society for the Prevention of Cruelty to Animals (ASPCA) website.