Yews are commonly used as landscaping plants as they stay green year-round. A pet looking for a bit of winter green may be tempted to take a nibble. Yews contain compounds that have a direction action on the heart. The toxins can cause an irregular heartbeat or even stop the heart. All parts, except for the ripe berry (a fleshy red structure surrounding the seed), are toxic. Sudden death can occur within hours of ingestion.