How poisonous are yew trees?
|This report serves exclusively to provide information about the toxicity of the various plant components of the yew. He should in no case encourage the yew resp. to abuse the yew poison in any form!|
|Yes, yew trees are poisonous, except for the red seed coat - the arillus - and therefore deadly for humans as well as for many animals in large enough quantities.|
For horses, for example, 100-200g of needles are enough to cause death. In relation to their high weight, they are particularly susceptible to yew poison. This is one of the reasons why the yew tree has been eradicated from our forests, which used to be farmed by horses! On the other hand, however, roe deer and deer can use the needles and other components such as e.g. B Eat the bark of the yew completely harmless. This is because they are ruminants and eat the food in several steps, resp. stomachs, rendering them harmless from taxation. Yew toxicity is mainly caused by two different alkaloids: taxine A (C 35 H 47 NO 10 ) and taxine B (C 33 H 45 NO 8 ). One of the derivatives of taxine A is paclitaxel, which is widely used to treat several types of cancer. Today, however, it is no longer made from parts of the yew tree, but purely synthetically. As with everything, the quantity makes the poison or even the cure.
The lethal dose for an adult corresponds to around 30-100g of fresh yew needles or fresh bark, depending on body weight and individual disposition. This must be oral resp. be absorbed via the gastrointestinal tract in order to develop their effect.
In this picture you can see a lethal dose of 50g yew needles
It should be noted that a study analyzing eight cases of intoxication showed that consumption of crushed or chopped yew needles resulted in a five times higher concentration of taxine breakdown products in the blood than consumption of intact needles. However, when preparing concoctions from yew needles, the toxicity is reduced over time due to the instability of the extract, especially in an alkaline environment. A quantity of around 250 mg of taxus alkaloid or about 3 mg of taxine per kilogram of body weight is lethal to humans. Another well-known rule of thumb for the lethal dose in humans is:
"One gram of fresh needles per kilogram of body weight"
But even just 10g of freshly crushed needles could be a lethal dose! However, this would have to be taken immediately after chopping, otherwise the mixture loses its effect relatively quickly!
Here is a graphic for the lethal dose of yew needles in humans and animals:
The proven concentration of the poison is by far the highest in the needles. In comparison, however, the wood is harmless. It contains around 6-10 times less of the toxins, in particular taxin B!
In the most recent examinations of the wood, no taxine B could be detected at all.
It should also be mentioned that yew wood has been processed by man into products for centuries, including bows and arrows, jewellery, furniture and much more! In the past, even taps or fountain spouts were made of yew wood because yew wood is so durable. Nowadays it is recommended to wear a dust mask when sanding yew wood, as the wood dust can cause allergic reactions. This is e.g. This is also the case with oak wood. It must also be mentioned that the effectiveness and content here only refers to the fresh and therefore "undried" condition of the plant components or the wood. As soon as a drying and decomposition process has taken place, the concentration of taxins gradually decreases as the toxins evaporate.
To get a lethal dose of yew wood, you would need to ingest around 500g of fresh wood orally and through the gastrointestinal tract. Eiben-Art products are therefore completely harmless as long as they are not eaten!
However, it should be mentioned that there are old reports of poisoning from wine stored in yew barrels! This is of course due to the wine's ability to extract the poison from the wood over time. However, since the oral intake of these large amounts of wood seems almost impossible even when using yew wood as a cutting board, our products made of yew wood can also be used in the kitchen without any danger. Which, by the way, they have been getting from us for years!
The use of yew wood for the production of drinking cups, tableware such as e.g. B Spoons, plates and other objects that are inserted orally, or used as containers for food and drink!!!