All of these species contain taxine in every part of the plant except in the aril,[citation needed] the fleshy covering of the seeds (berries).

[9] These species have distinctive leaves, which are needle-like, small, spirally arranged but twisted so they are two-ranked, and linear-lanceolate.

It grows well in steep rocky areas on calcareous substrates such as in the chalk downs of England, and in more continental climates it fares better in mixed forests.

[12] Greek and Roman writers have recorded examples of poisonings, including Julius Caesar's account of Cativolcus, king of Eburones, who committed suicide using the “juice of the yew”.

[14] In 1856, H. Lucas, a pharmacist in Arnstadt, prepared a white alkaloid powder from the foliage of Taxus baccata L. which he named taxine.

[4] For the next 60 years, it was generally accepted that taxine was made of a single compound and it was well known enough for Agatha Christie to use it as a poison in A Pocket Full of Rye (1953).

[25] Taxines are also absorbed efficiently via the skin and Taxus species should thus be handled with care and preferably with gloves.

[24] The estimated lethal dose (LDmin) of taxine alkaloids is approximately 3.0 mg/kg body weight for humans.

[29] Minimum lethal doses (oral LDmin) for many different animals have been tested:[29] Several studies[30] have found taxine LD50 values under 20 mg/kg in mice and rats.

The method of diagnosis is the determination of 3,5-dimethoxyphenol, a product of the hydrolysis of the glycosidic bond in taxine, in the blood, the gastric contents, the urine, and the tissues of the patient.

[35] Because taxine poisoning is often only diagnosed after the death of the patient due to its rapid effect, preventing exposure is very important.

Pet owners must ensure that yew branches or leaves are not used as toys for dogs or as perches for domestic birds.

With smaller doses, animals display uneasiness, trembling, dyspnea, staggering, weakness, and diarrhea.

"Necropsy findings are unremarkable and nonspecific", generally including pulmonary, hepatic, and splenic congestion.

[42] [1] Archived 2014-05-09 at the Wayback Machine Asheesh K. Tiwary, Birgit Puschner, Hailu Kinde, Elizabeth R. Tor (2005).

[2]Andrea Persico, Giuseppe Bacis, Francesca Uberti, Claudia Panzeri, Chiara Di Lorenzo, Enzo Moro, and Patrizia Restani (2011).

"Identification of Taxine Derivatives in Biological Fluids from a Patient after Attempted Suicide by Ingestion of Yew (Taxus baccata) Leaves".