How poisonous are yew berries?

People tend to overestimate the toxicity of yew seeds, because it doesn’t take much to kill certain animals with high sensitivity to the taxine, notably horses, or small animals even. When it comes to human, it takes a lot more, unless you have heart problems. We’re talking 300 for someone who weighs 50 kg, or... approximately 6 seeds/kg, and that’s at the low end. That said, it’ll take far less to kill a small child.