Leaves of Hemlock Water Dropwort
Leaves of the potentially deadly Hemlock Water Dropwort. Foragers have confused these with other members of the same family including Parsley, Wild Celery, Ground Elder, Alexanders, Common Hogweed and Lesser or Greater Water-Parsnip.

Cases of mistaken identity – confusing edible and poisonous plants.

If someone has accidentally consumed a poisonous plant, please see this information at the end of the blog post.

I don’t want to scare you or put you off but I’ve heard a few foraging horror stories recently. These are cases of mistaken identity, people consuming a poisonous plant thinking it was something edible. In this blog post, we look at the most common errors that are made, the identification of the poisonous species and some of these stories. This information is presented trying to avoid the same mistakes happening again. I’ve not gone that far back in time looking for these stories; a century or so ago they were more common place, and as treatments were less developed, the consequences often greater.

When I introduce people to foraging, plants or fungi, there are a few things that get repeated:

  • “If in doubt, leave it out” – if you are not 100% certain of what you are picking and that it is edible you shouldn’t eat it.
  • “Know your enemies” – don’t just know the good things to eat but be very familiar with the ones you shouldn’t pick and eat, that is the poisonous species.
  • If what you are picking is new to you, check the identification with at least two field guides. These are often better on identification then foraging books.

I strongly recommend that you spend time getting to know these four plants – the knowledge could save your life and the lives of your loved ones. Read and look at them in multiple books or online and track them down in the real world. Do not overly rely on online sources – some have errors!

Hemlock Water Dropwort (Oenanthe crocata)


Hemlock Water Dropwort is frequently described as ‘probably the most poisonous plant found in Britain’. No British wild plant has been responsible for more fatal accidents caused by identification mistakes. The whole plant, especially the roots, is extremely toxic with even a small amount ingested being deadly – you can be dead within 3 hours of consuming it. The mortality rate is quantity dependent but has been reported as between 30%–70%. If you a dog owner do be aware that a significant number of dogs die from eating it too.

The main toxic constituent of Hemlock Water Dropwort is oenanthotoxin.  Symptoms of Hemlock water Dropwort poisoning include nausea, increased salivation, and vomiting. There may be tremor, abdominal cramps, and diarrhoea. Seizures can rapidly develop, blood pressure falls. Acute renal failure has been reported too.

If you come into contact with it wash your hands as soon as possible and avoid touching your eyes and mouth.



Hemlock Water Dropwort and the next plant, Hemlock, are Umbellifers – members of the Carrot or Parsley family. With around 60 family members growing wild in the UK they are notoriously tricky to identify to species level. The defining feature of plants in this family is that the flowers are in flat-topped or rounded clusters – an umbel.

A flat-topped umbellifer
A flat-topped umbellifer


A rounded umbellifer
A rounded umbellifer

Note that touching some umbellifers followed by exposure to sunlight, may cause phytophotodermatitis, a serious skin inflammation. Symptoms of which include redness and blistering.

Descriptions for umbellifers use the word “pinnate”. This simply means “resembling a feather” having parts or branches arranged on each side of a common axis, in a plant the stem. In a bipinnate (or ‘twice pinnate’ leaf), the leaves are also divided. This idea is extended into 3 or 4 times pinnate.

Pinnate (left) and bipinnate (right) leaf structures
Pinnate (left) and bipinnate (right) leaf structures

Height: 1 – 1.5 m tall.

Stems: Grooved. Plant entirely hairless.

Flowers: July. Flower diameter c 2 mm. Groups or clusters c 5-10 cm (2 – 4 “) diameter.

Hemlock Water Dropwort Flower
Hemlock Water Dropwort Flower. Photo: H. Zell [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
Leaves: 3-4 times pinnate with toothed wedge-shaped segments. Dark green and look like flat-leaved parsley with a distinctive celery or parsley smell.

Leaves of Hemlock Water Dropwort
Leaves of Hemlock Water Dropwort

Roots: Distinctive. Cream / White, bunched.

Hemlock Water Dropwort drawing including roots
Hemlock Water Dropwort drawing including roots


Always found in wet areas such as streams, ditches, wet meadows, marshes, rivers and lakes. Note that following floods, the roots have been washed downstream onto beaches.

Hemlock Water Dropwort - always in or near water.
Hemlock Water Dropwort – always in or near water.

Edible Plants it might be confused with

The leaves look like flat-leaved Parsley. They can also be confused with other members of the carrot family such as Ground Elder, Alexanders and Common Hogweed as well as cultivated members such as Carrot and Parsnip. The roots known as “dead-man’s fingers” look a bit like cultivated parsnips or the roots of Lesser or Greater Water-Parsnip. The stems have been confused with Celery.


British and Irish examples of mistaken identify

Seeking Water Parsnip, consumed Hemlock Water Dropwort

A lady on one of my recent foraging courses told me that her brother had foraged for ages but confused Hemlock Water Dropwort with Water Parsnips. I don’t know all the details, but his flat mate came downstairs to tell him he was off to work an hour early and found him on the kitchen floor. The air ambulance came, and his heart stopped three times but survived. He still forages!

Seeking Water Parsnip, consumed Hemlock Water Dropwort

In 2002, a group of eight young adults who were on holiday in Scotland, consumed what they thought were Water Parsnips from a small stream in a curry. Over the next day there were seizures, nausea, vomiting, lethargy, sweating, and fever. While they were admitted to hospital a botanist identified the plant. Following treatment all were released from hospital. Source: British Medical Journal / BSBI News

Seeking Pignut, consumed Hemlock Water Dropwort

In 1976, a man living and working on a farm in Northumberland ate some Hemlock Water Dropwort root, assuming it was Pignut. 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. Source: The Poison Garden

Seeking Celery, consumed Hemlock Water Dropwort

In 1987 in Ireland, four Dutch holidaymakers mistook Hemlock Water Drop for Celery. They made soup with them. 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. Source: The British Medical Journal

Seeking Celery or Water Parsnips, consumed Hemlock Water Dropwort

In 1987, a young couple had a meal of ducks’ eggs, Nettles, and the boiled leaves and roots of Hemlock Water Dropwort picked beside the River Thames. Forty minutes later, he developed nausea, abdominal pain and other symptoms. On admission to hospital, he experienced major seizures. After considerable hospital treatment he survived. She ate less of the plant and made herself sick. She was released from hospital after 3 days.  Source: Postgraduate Medical Journal

Seeking Wild Celery, consumed Hemlock Water Dropwort

“So I was down in my allotment out on the cliffs near the coast path. I’d just popped by for 10 minutes to water some seedlings. Was just about to leave when I heard a tap on the door. It was a woman who’d been on one of my courses a few months ago and a few of her friends. (who hadn’t been on a course) They had a bunch of Three Cornered Leeks and had been out doing some foraging. All great. Had a nice chat about foraging. Then she casually mentioned in the conversation they’d eaten and picked some Wild Celery… Alarm bells ring.

I immediately got her to take me to the plant shed eaten and confirmed my worst fears that it was Hemlock water dropwort. Apparently they’d eaten a few of the leaves and experienced a burning sensation in the mouth. Much to their horror and initial disbelief I explained the severity of the situation, wrote down the name of the plant and informed them to get to hospital ASAP. They went to the local A & E and were transferred to the hospital for monitoring. Ive heard from them this morning and thank goodness both are okay. One was discharged late this morning and the other was on a drip overnight but okay now. Apparently they’d picked more to enjoy in a salad when they got home.I’m so glad I was there at that specific time.”

Source: UK foraging teacher

Seeking Alexanders, nearly consumed Hemlock Water Dropwort

“A couple of days ago the wife of my housemate asked how best to cook Alexander’s as some was on the way. Onions were frying in anticipation when the Hemlock Water Dropwort arrived!”

Source: UK foraging teacher

Seeking Alexanders, nearly consumed Hemlock Water Dropwort

In April 2017, a lady posted in a Facebook group her photo of the “Alexanders” she had gathered for a risotto. It was actually Hemlock Water Dropwort. Fortunately a foraging teacher saw the post. There was then a mad scramble to try to find contact details for her. The search was succesfull and the teacher managed to phone her before she ate it potentially saving the lives of her and her family!

Source: UK foraging teacher

Hemlock (Conium maculatum)


Hemlock is deadly poisonous with no antidote to the toxins in it. Famously, it was used to put Socrates, and other prisoners, to death in the Ancient World. Chances of recovery increase markedly if it is diagnosed early. The toxins in Hemlock are alkaloids which cause vomiting, headaches, abdominal pain and muscular paralysis, leading to seizures, coma, respiratory failure and eventually death. Only a tiny amount of Hemlock can prove fatal. The toxins can also be absorbed through the skin, so if you come into contact with it wash your hands as soon as possible and avoid touching your eyes and mouth.



Height: 1.5 – 2.5 m tall.

Stems: Thick, smooth green stem, hairless, usually spotted or streaked with red or purple on the lower half of the stem (older plants are spotted).

Leaves: Main leaves twice pinnately divided, broadly feathery. Up to 50 cm long and 40 cm broad.

Hemlock stems and leaves.
Hemlock stems and leaves. Photo: MPF [CC BY-SA 3.0 (https://creativecommons.org/licenses/by-sa/3.0)]
Smell: “Nasty” – often described as mouse-like, musty or like parsnips.

Flowers: The flowers are small, white, clustered in groups up to 10–15 cm (4 – 6”) across.

Hemlock flowers
Hemlock flowers. Photo: Mick Talbot from Lincoln (U.K.), England [CC BY 2.0 (https://creativecommons.org/licenses/by/2.0)] via Wikimedia Commons


Mainly wet places – on poorly drained soils, particularly near streams, ditches, and other surface water. Also, on disturbed ground such as roadsides and the edges of cultivated fields.


Edible Plants it might be confused with

Leaves look a bit like (cultivated) Parsley or Cow Parsley. The roots like those of Lesser or Greater Water-Parsnip.


British and Irish examples of mistaken identify

Seeking – unknown edible plant, consumed Hemlock

In 2001, a leading neurosurgeon and his companion were both seriously ill and hospitalised after eating what is believed to be Hemlock. The male was unconscious by the time he reached hospital in Inverness. He regained consciousness a day or so later and his condition, which had been life-threatening, was described as stable. His companion was released from hospital after a few days and he fully recovered over a long period.

Source: The Guardian

Seeking Wild Parsnip, consumed Hemlock

In 2018 in Dorset a forager accidentally consumed Hemlock when he hoped to find Wild Parsnip. It is not known what part of the plant, how much was consumed or if it was cooked. Shortly after eating it, he identified that his heart was racing and phoned his girlfriend to tell her what he had done. He asked her to ring him regularly and if he didn’t answer to call 999!


Lords and Ladies (Arum maculatum)

Lords and Ladies is known by many different names including Cuckoo Pint and Wild Arum.


Consuming the leaves and berries of Lords and Ladies give an immediate burning sensation to lips and throat followed by significant swelling which can result in difficulty breathing.

The berries are one of the most common causes of accidental plant poisoning based on attendance at hospital accident and emergency departments. These are most often consumed by children. Usually the immediate burning in the mouth means they are rarely ingested.



Lords and Ladies (Wild Arum / Cuckoo Pint) - Photo by Sannse, 24 April 2004, Essex, England.
Lords and Ladies (Wild Arum / Cuckoo Pint) – Photo by Sannse, 24 April 2004, Essex, England.

Height: Up to 40 cm tall.

Flowers: Chocolate coloured poker-shaped “flower” partially enclosed in a leaf-like hood.

Leaves: A larger leaf is arrow-shaped to triangular and has rounded, backward facing lobes – a bit like an arrow head. Younger leaves do not have the lobes but still have prominent veins. The leaves may have blackish / purple spots.

Lords and Ladies / Cuckoo Pint / Wild Arum leaves
Lords and Ladies leaves at varying stages of growth (light green leaves to near left and right edges of the photograph are another plant).

Berries: In Autumn a cluster of bright red berries

Lords and Ladies berries (Arum maculatum)
Lords and Ladies berries (Arum maculatum) – Paul Henderson [CC BY-SA 3.0] via Wikimedia Commons


Woodlands, hedgerows, gardens and shady places.


Edible Plants it might be confused with

Sorrel. The backwards pointing lobes on Sorrel leaves are pointed (like cut with scissors), on Lords and Ladies they are rounded.  Lords and Ladies leaves also have irregular edges and many deep veins. Sorrel is a plant of grassy fields, Lords and Ladies more shady places.

Sorrel (left) and Lords and Ladies (right)
Sorrel (left) and Lords and Ladies (right). NB Sorrel lobe tips have curled upwards but are V -shaped.

Wild Garlic. Smaller Lords and Ladies leaves can look more like a Wild Garlic leaf, but the veins should still be obvious. They won’t smell of Garlic! Wild Garlic leaves are long, pointed, “spear-shaped”. They do not have veins – just a prominent central mid-rib (looking like an extension of the stalk).

In the below photograph we have – from left to right:

1. Lords and Ladies – rear
2. Lords and Ladies – front
3. Wild Garlic – front
4. Wild Garlic – rear

Leaf comparison - Lords and Ladies and Wild Garlic
Leaf comparison – Lords and Ladies and Wild Garlic (see below).

British and Irish examples of mistaken identify

Seeking Wild Garlic, consumed Lords and Ladies

In April 2018 in the UK, a whole family were hospitalised for confusing Wild Garlic with Lords and Ladies.

Seeking (Common) Sorrel, consumed Lords and Ladies

I am personally aware of cases of inexperienced foragers eating young Lords and Ladies leaves when they were hoping to find Sorrel. The immediate burning sensation on the lips and mouth means it was spat out and they realised their mistake. There are many similar tales on the Internet.


Dog’s Mercury (Mercurialis perennis)


Symptoms of poisoning from consuming Dog’s Mercury appear within a few hours; they can include vomiting, pain, gastric and kidney inflammation, and sometimes inflammation of the cheeks and jaw and drowsiness. Larger doses cause lethargy, jaundice, painful urination and coma before death.


Dog's Mercury
Dog’s Mercury

Height: Up to 40 cm tall.

Stems: Downy / hairy

Flowers: Clusters of small cream / green flowers on upright, tassel-like spikes.

Leaves: Spear-shaped, toothed, fresh green leaves



Woodlands and hedgerows where it can form a dense carpet.

Edible Plants it might be confused with

The main risk is accidentally gathering some when picking Wild Garlic or Nettles which it can grow amongst. Dog’s Mercury has however been confused with Ground Elder and Brooklime, furthermore, it could also be mistaken for a member of the Goosefoot genus.

Dog's Mercury in amongst Nettles
Dog’s Mercury in amongst Nettles

British and Irish examples of mistaken identify

Seeking Ground Elder, consumed Dog’s Mercury

In April 2017, a runner paused to take a break. Mistaking Dog’s Mercury for Ground Elder he ate a handful of the plant. The result was an increase in saliva and a feeling of nausea. He eventually vomited and was able to expel the plant from his body.

Source: The Poison Garden

Seeking Brooklime, consumed Dog’s Mercury

In 1983, a couple washed, boiled and ate a large quantity of Dog’s Mercury leaves after mistaking it for Brooklime. Both of them were hospitalised complaining of nausea, vomiting, and severe pain and presenting signs similar to an allergic reaction. They recovered after treatment and two days of rest and continuous observation and monitoring.

Source: British Medical Journal

Seeking a salad leaf, consumer Dog’s Mercury

In 2017, a lady picked some Dog’s Mercury and ate it in a salad. Luckily, she didn’t feel happy with it and only ate a little, but that was enough to cause her lips, mouth and throat to burn. This was followed by a feeling of shaky weakness and a need for the toilet.

Source: Nature’s Secret Garden


Further reading

Mark Williams of Galloway Wild Foods wrote an excellent article for a magazine on foraging and umbellifers. You can find it here (PDF).

Poisonous Plants in Great Britain by Fred Gillam (book)

The Poison Garden (web site)

Foxglove and other poisonous plants (web site)


What to do in the case of accidentally consuming a poisonous plant

Adapted from NHS poisoning treatment information. Numbers / links are for UK residents.

Being poisoned can be life-threatening. If someone has eaten a poisonous plant (or fungus), don’t try to treat them yourself – seek medical help immediately.

If they’re showing signs of being seriously ill, dial 999 to request an ambulance or take them to your local A&E department.

Symptoms associated with serious poisoning include:

Call NHS 111 for advice if a person who’s been poisoned doesn’t appear to be seriously ill.

Helping someone who’s conscious

If you think someone has been severely poisoned and they’re still conscious, ask them to sit still and stay with them while you wait for medical help to arrive.

If they’ve been poisoned by eating a plant, try to get them to spit out anything that is remaining in their mouth.

Helping someone who is unconscious

If you think someone has eaten a poisonous plant and they appear to be unconscious, try to wake them and encourage them to spit out anything left in their mouth. Don’t put your hand into their mouth and don’t try to make them sick.

While you’re waiting for medical help to arrive, lie the person on their side with a cushion behind their back and their upper leg pulled slightly forward, so they don’t fall on their face or roll backwards. This is known as the recovery position.

Wipe any vomit away from their mouth and keep their head pointing down, to allow any vomit to escape without them breathing it in or swallowing it. Don’t give them anything to eat or drink.

If the person isn’t breathing or their heart has stopped, begin CPR (cardiopulmonary resuscitation) if you know how to.

How to help medical staff

Medical staff will need to take a detailed history to effectively treat a person who’s been poisoned. When the paramedics arrive or when you arrive at A&E, give them as much information as you can, including:

  • what plant you think the person may have eaten
  • when the plant was eaten (how long ago)
  • if it was cooked
  • how much was eaten (if you know)
  • Details of any symptoms the person has had, such as whether they’ve been sick.

Take a sample of the plant with you – as many parts of the plant as you can for accurate identification – e.g. leaves, flowers, fruits, stem and roots. If there is any of the food left over take a sample of that too.

Medical staff may also want to know:

  • the person’s age and estimated weight
  • whether they have any existing medical conditions
  • whether they’re taking any medication (if you know)

There is an excellent Facebook group Poisons Help; Emergency Identification For Mushrooms & Plants. If you can post pictures of the plant / fungi and give your geographic location (e.g. Dorset / UK) you will get a rapid identification from extremely knowledgeable people around the globe.