Some poisonous plants can be extremely dangerous and cause death, but they can also be used to make powerful medicines.

An astonishing phenomenon detailed by biologist Katia Astatieff, Thursday in the program Sans Rendez-vous on Europe 1.

Nature is full of thousands of species of plants.

However, some of them can be very dangerous and cause severe pain if touched, and even lead to death.

But these poisonous plants are also used in the manufacture of certain drugs, such as an anticancer.

Katia Astafieff, biologist and deputy director of the Botanical Gardens of Grand Nancy, mentioned these plants on Thursday on Europe 1 in the program Sans Rendez-vous. 

>> Find all of Sans rendez-vous every day from 3 p.m. to 4 p.m. on Europe 1 as well as in replay and podcast here

Urtica ferox and giant hogweed: these plants that cause unbearable pain 

Some plants are so poisonous that they can cause severe pain just to touch.

This is the case with urtica ferox, also called ongaonga, which lives in New Zealand.

But "the worst lives in Australia: the dendrocnide moroides", explains the biologist, author of the book

Bad seeds, the surprising history of the plants which sting, which burn and which kill

.

"I found the testimony of an American student who, in contact with the plant, had the sensation of both being electrocuted and being sprayed with hot acid," explains Katia Astafieff.

"This plant causes very intense pain, since it will emit toxins called 'moroidines'. This toxin will cause intense and unbearable irritation. People who have touched the plant say they are going crazy and tell of unbearable pain" . 

Another extremely dangerous plant: giant hogweed.

"It is a very beautiful plant that looks like a giant carrot, shaped like an umbrella. It is said to be invasive, that is to say it spreads considerably. Above all, it is photo-sensitizing, if we touch it before or after being exposed to the sun we risk very intense burns. It can be third degree burns. These are plants that should not be touched ", warns the biologist.  

Poisonous plants that can be used as medicine ...

Some poisonous plants are used to make medicines.

"It is a basic rule of pharmacology. The same molecule at a very small dose can heal, but at a higher dose can kill", explains Katia Astafieff.

"There are plants which manufacture toxic molecules, which are defense mechanisms. We have the example of the yew, which is a very beautiful tree, all parts of which are poisonous and which is fatal (and that the 'we can find in France) ", warns the biologist.

"But with this plant we have managed to manufacture one of the most important drugs today, since it is made into a very powerful anticancer."

... or as poison 

Do you know the vomiter?

This plant was used to make a medicine, but also by serial killers.

Because the fruit of strychnos nux-vomica, its scientific name, contains a poison: strychnine.

"It has been used in certain medicines but also to commit murders. It is found in fiction, in the novels of Agatha Christie and Alexandre Dumas. A Canadian serial killer also used it at the end of the 19th century by poisoning women with strychnine ".