London - Gelsemium elegans is pretty but highly toxic yellow-flowered shrub, known as heartbreak grass, found only in remote regions of China.
Just a few drops in the bloodstream can trigger cardiac arrest, making it appear that the victim has suffered a heart attack.
In 2012, police investigating the death of millionaire tycoon Long Liyuan in southern China suggested he may have been poisoned by gelsemium slipped into a cat stew he was eating in a restaurant.
There are three species of gelsemium, all poisonous. In tiny quantities, it has been marketed as a homeopathic remedy for migraine, asthma and even malaria.
In 1879, Sherlock Holmes author Sir Arthur Conan Doyle described administering himself small but increasing amounts of gelsemium until he could not stand the ill effects.
Daily Mail