You must have heard about poisonous plants, but have you ever heard about a plant so deadly that it leaves its victims with a sinister looking grin? Water hemlock (Cicuta), also known as cowbane ...

Italian scientists believe they have solved an ancient medical mystery which gave the world the expression 'sardonic grin'.

The term sardonic grin comes from the grisly practice in 8th Century Sardinia of disposing of criminals and old people using Hemlock Water Dropwort.

You must have heard about poisonous plants, but have you ever heard about a plant so deadly that it leaves its victims with a sinister looking grin?