Fans of the HBO series Game of Thrones were shocked, surprised and satisfied when one of the programme's best villains, King Joffrey, was poisoned at his own wedding.

In an episode dubbed the Purple Wedding, because of the hue of the king's face, viewers bid farewell to the sadistic monarch as he lay twitching and red-eyed in his mother's arms.

Using details from George RR Martin's books, the American Chemical Society has tracked down the mystery poison, which has been described only as "the strangler".

In the society's latest Reactions video on YouTube, Raychelle Burks, a chemist at Doane College in Nebraska, explains what the ancient poison is - and whether the chemical could still be used.

The strangler is rare and unknown to most of Westeros, the fictional land in which the series is set, but there are clues that indicate what the poison could be. The book states it is made "from the leaves of a plant" that thrives on an island in the "Sea of Jade".

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With this information, Burks suggests there are three potential plant-based poisons. Deadly nightshade, also known as belladonna, poison hemlock and the strychnine tree are all candidates.

Highlighting that Joffrey suffocated as his was dying - hence his purple face - and that the king's eyes and nose started bleeding, Burks suggests only one of the three poisons is likely. Belladonna and hemlock make the muscles relax. Joffrey's asphixiationcould only have been caused by strychnine, which causes the muscles in the face and neck to contract.

The book also states that the compound is extracted using a "wash of lime", before it is treated with a "rinse of sugar". Rather than the lime fruit, Burks suggests the lime refers to a limestone product, calcium oxide. Calcium oxide is used in one of the processes to extract alkaloids, such as strychnine, from plants.

And as for the sugar? It was used to mask strychnine's bitter taste.

"Sometimes science gets a bad rap," Burks told Science Codex. "People think it's dry or super serious. Pop culture is really a good medium to talk about science in a way that anyone and everyone can participate."

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