Yes, English Yew is toxic to dogs!
Dogs accidentally consuming the English 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).
English Yew consumption is also toxic to Cats and Horses.
Toxic Principles Of English Yew: Taxine A and B, Volatile oil.
More Info About The English Yew Plant
Scientific Name: Taxus baccata
Family: Taxaceae.
Also known as: Western Yew, Pacific Yew, Japanese Yew, Anglo-Japanese Yew.
The answer is based on information found on The American Society for the Prevention of Cruelty to Animals (ASPCA) website.