Yes, Yew is toxic to dogs!
Dogs accidentally consuming the Yew 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).
Yew consumption is also toxic to Cats and Horses.
Toxic Principles Of Yew: Taxine.
More Info About The Yew Plant
Scientific Name: Taxus spp.
Family: Taxaceae.
Also known as: japanese yew.
The answer is based on information found on The American Society for the Prevention of Cruelty to Animals (ASPCA) website.