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Oenanthe crocata, hemlock water dropwort
Though somewhat similar in appearance to the poison hemlock, this plant kills much more quickly. So quickly, that, historically, it hasn't always been identified as the cause of sudden death.
Read more about Oenanthe crocata, hemlock water dropwort, in these blog
entries (most recent first);
Beautiful stands of plants at Bryngwyn Hall
First person account of the effects of chewing small amount of leaves
Confusion over plant naming because 'hemlock' is many plants
A seventeenth century poisoning incident resulting in five deaths
A correspondent recalls his own experience of 'living off the land'.
The unanswered questions about poisoning incidents.
An unsuccessful walk to get new video footage because high river flows have knocked the plant over.
Would you mistake hemlock water dropwort for coriander?
Apiaceae. The synonym Umbelliferae is also used.
Meaning of the Name
From the Greek ‘oinis’, ‘wine’ and ‘anthos’. ‘flower’ and usually said to be because the smell of the flower is like wine but it may be that the giddiness produced from smelling the flowers is like the effect of wine.
Like a crocus, that is having a saffron yellow colour. This may be a reference to the yellow colour of the seeds and be an attempt to distinguish the plant from other hemlocks.
Common Names and Synonyms
hemlock water dropwort, water hemlock, dead man’s fingers
How Poisonous, How Harmful?
Oenanthe crocata, hemlock water dropwort
This plant is frequently described as 'probably the most poisonous plant found in Britain'. In 1987 it was said that there had been fourteen reported cases in the 20th century, nine of which were fatal.
It contains oenanthetoxin, a poly-unsaturated alcohol similar to the cicutoxin found in Cicuta spp. (Cicuta maculata is more usually called water hemlock.)
The roots contain the greatest concentration. It is sometimes said that the toxins are stronger in the winter but it may be that, in the absence of other vegetation, of the toxins, especially in the winter. A small amount of raw plant material is fatal causing nausea, convulsions, excessive salivation and dilated pupils. Death comes quickly. The roots have been eaten in mistake for parsnips and the stems have been eaten as celery.
Thomas Johnson was born in Selby, Yorkshire early in the 17th century. The first record of him being involved with plants shows that he was in London by 1626.
In 1629, he joined an expedition of apothecaries intent on exploring an area and documenting, for the first time, the plants found there. The expedition was to Kent. One of the plants they brought back which had never before been found to grow in England was Cannabis sativa, marijuana.
In 1633, his extensively revised version of John Gerard’s ‘Great Herbal’ was published. It added 800 plants and 700 illustrations to Gerard’s work and Johnson accused Gerard of dishonesty as well as mocking his gullibility (Gerard believed that Barnacle geese were the fruit of an exceptional tree).
Johnson was undoubtedly a better botanist than Gerard and his 1633 revision is the definitive version of the ‘Great Herbal’.
It is probable that Cicuta maculata has the best claim to the name water hemlock since the maculata, meaning speckled, means it looks most like the Conium maculatum, poison hemlock.
The book 'Poisonous Plants and Fungi' says vomiting occurs with both O. crocata and C. virosa the former within an hour of ingestion. Frohne and Pfander in 'A Colour Atlas of Poisonous Plants' say Cicuta and Oenanthe have the same effects but the MAFF publication 'Poisonous Plants in Britain and their effects on Animals and Man' gives nausea and vomiting in the list of effects of Cicuta virosa but says that death from Oenanthe crocata, in animals, is quick and may be symptomless.
The smell of the plant causes giddiness.
In March 2015, a visitor to this site provided a first person account of their experiences after chewing just a very small number of young leaves. The account can be found in the blog for 11th March 2015.
During the Napoleonic Wars with France, eleven French prisoners were allowed out to walk near Pembroke. Three of then dug up a large quantity of Oenanthe crocata and ate some of the roots. Shortly after, one of them suffered severe convulsions and quickly died. Since the other two were well they did not suspect the plant and went on to feed it to the other eight prisoners. During dinner, these two began exhibiting symptoms from which one died. Now realising what had caused the poisoning, the rest were made to vomit in time to prevent them being harmed.
As above, there were, at least, fourteen cases of hemlock water dropwort poisoning in Britain in the 20th century. The following are brief accounts of three of these incidents.
A visitor to this site told me of his experience of Oenanthe crocata poisoning in 1976. Whilst living and working on a farm in Northumberland during his summer vacation, he ate some root, assuming it was pignut, Conopodium majus. He survived thanks to a combination of three things; his own prompt action when he realised something was 'awry', the farmer being easily found to get him straight to hospital and the A & E registrar who consulted an expert at Newcastle University. The full story is given in this blog entry and I particularly recommend it to anyone thinking of saving money in these straitened times by making the most of 'food for free'.
Oenanthe crocata leaves
In the 1980s, a young couple made themselves a meal using nettles and the leaves and roots of Oenanthe crocata, apparently thinking it was wild parsnip. Poisoning became apparent after forty minutes and the man was admitted to hospital with a variety of symptoms including nausea and convulsions which were so severe that a paralysing agent was required. After 60 hours he was well though elevated levels of enzymes related to the poisoning were still measured after 10 days. His girlfriend ate much less of the meal and, as soon as his symptoms appeared, made herself vomit which greatly reduced the effects. Normally, cooking would be expected to destroy some or all of the toxins, see below, but that does not seem to have happened in this case.
In Ireland it was reported in 1987 that four Dutch tourists collected hemlock water dropwort and made a soup. Seven hours after eating they all attended hospital complaining of nausea and vomiting; two suffered convulsions and one a seizure. Their symptoms were not, however, severe and all four were released from hospital after three days. Oenanthetoxin, though highly toxic, is quite unstable and the cooking process is believed to have destroyed much of it.
It appears that the new century has continued to produce the occasional poisoning incident.
Oenanthe crocata seed head
In a case reported in 2002, eight young people, on holiday in Scotland, collected what they thought were water parsnips and cooked them in a curry. Some of the group were unsure of the safety of eating the plant and others found the taste too bitter. It was ten hours after the meal that one of the group suffered a seizure and was taken to hospital. As with the French prisoners, no connection was made to the meal and four of the group finished the leftovers for lunch. Following another case of seizure they all attended hospital and, in total, four of them required admission.
Though Oenanthe crocata was suspected, the late onset of symptoms was confusing. The police took one of the well members of the group back to the riverbank where plant material was collected and positively identified as hemlock water dropwort.
The incident occurred in April and it is believed that the plant loses toxicity as the ground warms up but, it was generally agreed that the act of cooking had destroyed a large part of the oenanthetoxin thus accounting for the relatively mild effects.
At the end of May 2010, reports from China said that six people had died, with another seven taken seriously ill in the Xinjiang Uygur autonomous region. Details are sketchy but, it seems, the victims, all mine workers, ate 'herbs' thinking they were celery. Four of the victims died before reaching hospital and the other two died that evening.
The reference to celery and the speed of death suggests that Oenanthe crocata, or a very similar plant, may be the cause.
Folklore and Facts
Thomas Johnson was concerned that apothecaries did not know enough about plants to avoid being supplied with the wrong ones by the women who gathered and sold them. He implies that this mistaken supply may not, always, have been an innocent error on behalf of the gatherers. He notes that hemlock water dropwort is to be easily found at the Horse Ferry near Lambeth. The plant, he says, is often sold as peony.