Yes, Running Myrtle is toxic to dogs!
Dogs accidentally consuming the Running Myrtle 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).
Running Myrtle consumption is also toxic to Cats and Horses.
Toxic Principles Of Running Myrtle: Vinca Alkaloids.
More Info About The Running Myrtle Plant
Scientific Name: Vinca rosea
Family: Apocynaceae.
Also known as: Periwinkle, Vinca.
The answer is based on information found on The American Society for the Prevention of Cruelty to Animals (ASPCA) website.