Poisonous plants are a major cause of economic loss to the livestock industry. They can cause death, abortion, poor production, and birth defects, to name a few. Each year these plants adversely affect 3%–5% of the cattle, sheep, and horses that graze Western ranges.

Two such plants common to Oregon are poison hemlock and Western waterhemlock. Ingestion of either by humans or livestock typically results in death.

The deadly properties of hemlock have been known for centuries. Socrates is the most famous victim of these properties; he was forced to drink a toxic potion made from hemlock in 329 B.C. Native Americans also used the juice of the hemlock plant to poison the tips of their arrows.

In the past, the roots of poison hemlock have been mistaken for wild parsnips and eaten by people. A Tacoma, Washington, woman apparently put hemlock in a salad she ate and died. Stories abound regarding pets dying from encounters with it in fields, or children making whistles or snorkels from the hollow stems of these plants and becoming ill and succumbing to the toxic alkaloids present in all parts of the plant.

Let’s look at the differences between these deadly plants and include some strategies for eliminating them from your property.

Poison hemlock, Conium maculatum

Poison hemlock, also called poison parsley, is a member of the plant family Apiaceae. Other members of this plant family include carrots, celery, and parsnip. Like other members in this plant family, poison hemlock flowers have white, umbrella-shaped clusters in addition to the fernlike appearance of the leaves. This why people over the years have mistaken poison hemlock for wild carrot, wild parsnip, or wild parsley.

This plant is distributed throughout North America and was brought here by Europeans sometime in the 1800s. Poison hemlock quickly escaped their gardens and now infests roadsides, creeks, irrigation ditches, cultivated fields, and pastures. Poison hemlock typically grows in wet soils, but on occasion can tolerate semi-dry soils. It has been found in gardens, in pastures, and in crops.

Identification

Poison hemlock grows into a rosette the first year but does not flower until its second year. Each flower develops into a green, deeply ridged fruit that contains several seeds. After maturity, the fruit turns grayish brown. It is a biennial, or sometimes in favorable conditions it may be a perennial, growing 3–8 feet tall and occasionally reaching 10–12 feet.

During the first year of growth, poison hemlock forms a large rosette and usually remains in the vegetative stage. During the second year, it produces tall stems and then flowers. The large, dried stems have been known to remain toxic for up to three years.

Poison hemlock can be differentiated from a carrot or parsnip plant by the profuse number of purple spots on the stem. Leaves are also smooth and hairless.

Poison hemlock can be differentiated from a carrot or parsnip plant by the profuse number of purple spots on the stem. In addition, the stem is smooth and hairless. Leaves are also smooth and hairless; they are large, glossy green, finely divided and fern-like. Eight known alkaloids contribute to poison hemlock’s toxicity. Poison hemlock typically produces a bad smell that closely resembles mouse urine. This unpleasant odor is especially noticeable when the leaves are crushed.

Toxicity

All parts of poison-hemlock (leaves, stem, fruit, and root) are poisonous. Leaves are especially poisonous in the spring, up to the time the plant flowers.

If the plant is disguised in hay or pasture grasses and ingested, it only takes a small amount to kill. Also avoid silage with hemlock in it.

The good news for livestock producers is animals will avoid this plant as long as there is quality feed available. However, if the plant is disguised in hay or pasture grasses and ingested, it only takes a small amount to kill. Sheep may be poisoned by eating as little as 4–8 ounces of green leaves. Cattle that eat as little as 10–16 ounces may be affected. All classes of livestock and wildlife are susceptible to poison hemlock.

Signs of poisoning usually appear within an hour after an animal eats the plant. Animals die from respiratory paralysis in 2 to 3 hours. Signs to look for in animals include:

a loss of appetite

excessive salivation

bloat

a rapid but feeble pulse

evidence of muscular incoordination, and

the appearance of great abdominal pain.

Other signs include muscle tremors, frequent urination, defecation, and “nervousness.” In animals that die, breathing ceases due to respiratory paralysis before cardiac arrest.

Birth defects due to ingesting sub-lethal amounts of poison hemlock occur in all livestock and may include crooked legs (crooked calf disease, arthrogryposis), cleft palate, and kinked tails. Arthrogrypotic skeletal malformations occur in calves when poison hemlock is ingested by pregnant cows between days 40 and 70 of gestation. For sheep, goats, and pigs, these problems occur when animals are exposed to hemlock during the 30- to 60-day period of gestation. In addition, poison hemlock poisoning is indistinguishable from lupine-induced “crooked calf disease” without a necropsy.

Management

Mechanical treatment

Plowing or repeated cultivation will prevent poison hemlock from establishing. Digging poison hemlock can be effective when caught early and the plant population is small. Take care when digging or mowing poison hemlock. Wear rubber gloves and a mask when handling this plant. On a hot day, the plants’ toxins may be absorbed into the skin.

Do not burn the plant, as the smoke can contain deadly toxins. In fact, hemlock is so poisonous that some of poison hemlock’s alkaloid compounds have the ability to pass into milk when animals feed on sublethal amounts of this plant, which can adversely alter the flavor and safety of milk used for human consumption.

Chemical

Treating poison hemlock with herbicides is most effective in late spring or early summer. Several combinations of herbicides are effective, including 2,4-D plus dicamba (2.5lb + 1 lb a.i./acre). Glyphosate and triclopyr have also been used with success. Herbicides should be used on seedlings or small rosettes and not on fully mature plants for ultimate success. To achieve complete eradication, repeated applications may be required until the seed bank has been depleted.

Please use caution; herbicides sprayed within 50 feet of a body of water can pose significant environmental hazards and typically require an aquatic herbicide. Be sure to contact your local weed control authority or OSU Extension for specific herbicide recommendations, and check the herbicide label for restrictions.

Western waterhemlock, Cicuta douglasii

Western waterhemlock is a member of the plant family Apiaceae. It is described as the most violently toxic of all North American plants. It only takes a piece of the root the size of a walnut to kill a 1,200-pound cow or horse. Also known as cowbane, wild parsnip, and beaver poison, this plant is herbaceous and thrives along streams, marshes, rivers, and irrigation ditches all over the Western United States and Canada.

Identification

Western waterhemlock grows from 2 to 8 feet tall, depending on its location. The stems are hollow, and it is easily identifiable by its root — a bulbous structure that is mostly hollow, with the exception of a few partitions that form distinct chambers. Thick, fleshy tubers and slender individual roots grow from the bottom of the main rootstalk.

Seeds from plants growing along irrigation canals can be transported by water or mud to other locations and can remain viable in soil for up to three years.

The leaves of western waterhemlock are arranged like a feather, dividing 1–3 times into narrow-toothed and lance-shaped leaflets 1–4 inches long. The leaflet veins run from the midrib to the notches along the leaf edges, and then branch to the teeth-like tips. Like poison hemlock, Western waterhemlock’s flowers are white and grouped in umbrella-shaped clusters.

Likewise, each flower is two-seeded. The tea-colored seeds are somewhat kidney-shaped with corky ridges. Western waterhemlock reproduces from seed and vegetatively through overwintering root structures. Seeds from plants growing along irrigation canals can be transported by water or mud to other locations and can remain viable in soil for up to three years.

Toxicity

The toxic substance in waterhemlock is cicutoxin, a highly poisonous unsaturated alcohol that has a strong, carrot-like odor. It is found principally in the tubers or roots but is also present in the leaves, stems, and immature seeds. If the tuber is cut or broken, it exudes a highly poisonous brown or straw-colored liquid. This liquid is deadly; animals have been poisoned after waterhemlock roots were trampled in the water, releasing the toxic liquid.

Livestock that ingest just the upper part of the plant may survive, as this part is not as toxic as the roots. But that is not as common. Typically, cattle pull the whole plant out of the soil due to the wet conditions and eat it, root and all. This is always fatal. Cattle are common victims, but horses, sheep, and swine are sometimes killed, too.

Management

All classes of livestock and wildlife are susceptible to poisoning, with cattle, goats, and horses being the most sensitive. Most animal losses take place in the spring, as it is one of the first plants to emerge. Fortunately, animals tend to avoid this plant when other forage is available, but they will consume it when grazing is poor. Consumption and poisoning may also occur when hemlock is present in green chop, silage, or hay. Even when it is mature and dried out, it still possesses toxins.

Fortunately, animals tend to avoid this plant when other forage is available, but they will consume it when grazing is poor.

The best way to avoid livestock losses from western water hemlock poisoning is to eliminate it. If eradication is not complete, then areas known to be infested with Western waterhemlock, especially in the early spring, need to be strictly avoided. Use fencing or move livestock to other paddocks. Similarly, it is critical when cleaning ditches or clearing land to avoid exposing the toxic roots of waterhemlock, which then can be more easily ingested by livestock.

Mechanical control

Hand-pulling Western waterhemlock is effective when the soil is moist. Be careful to pull the entire plant, including all roots, and dispose of it in a garbage bag. Several articles recommend burning hemlock after pulling, but the smoke may contain toxins that could cause severe illness and even death. Be sure to wear appropriate gloves, as contact dermatitis is possible. If your hands come into contact with the plant — especially the root — and then touch your eyes or mouth, you can become very ill.

Chemical

For western waterhemlock, application of chemicals is most effective in late spring or early summer. Several types of herbicide can be effective, including Glyphosate, 2,4-D, and picloram and 2,4-D, and MCPA. Glyphosate is nonselective, so exercise caution to minimize injury or mortality of desirable plants that might help suppress new poison hemlock seedlings.

Keep animals away from treated plants for three weeks after spraying.

Also, after Western water hemlock is sprayed with herbicides, an increase in palatability can occur. Keep animals away from treated plants for three weeks after spraying. Chemical treatment of Western waterhemlock may require repeated applications to deplete the seed bank.

A word of caution: Herbicides sprayed within 50 feet of a body of water can pose significant environmental hazards. These situations typically require an aquatic herbicide. Be sure to contact your local weed control authority or OSU Extension office for specific herbicide recommendations. Check the herbicide label for restrictions.

Both poison hemlock and Western waterhemlock plants require caution when handling. Constant vigilance is required to eliminate these toxic weeds from your property. A good manager can contain or eliminate hemlock in order to keep your livestock safe.

References

UK health officials have issued hygiene advice after a rise in a strain of E. coli infections, with young children the most affected.

Cases of Shiga toxin-producing E. coli (STEC) jumped by over 25% in 2024, according to new UK Health Security Agency (UKHSA) figures. The spike was partly down to an outbreak linked to contaminated salad leaves, which caused nearly 200 cases in England alone.

Experts also warned that visits to petting farms and animal contact played a role – especially in kids aged one to four, who had the highest infection rates.

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STEC bacteria are spread through contact with animals or their faeces, consuming contaminated food or water, and from person to person. They can cause stomach cramps, vomiting, dehydration and diarrhoea. While most cases clear up on their own, some can be more serious and in rare cases life-threatening.

STEC cases have been gradually rising since 2022 and the UKHSA is urging people to take simple hygiene steps:

If you have symptoms, wash hands properly with soap and warm water and clean surfaces with bleach-based products

Don’t prepare food for others if you’re feeling unwell (or for 48 hours after symptoms stop)

Ensure children wash and dry hands thoroughly before eating, especially after playing outside or touching animals

Cook meat thoroughly, keep food chilled, and avoid cross-contamination

Bagged lettuce can contain food poisoning germs such as E coli, Salmonella and Listeria. (Image: Getty)

In June, UKHSA data also showed that cases of two of the most common food poisoning bugs had risen in 2024. Salmonella, often caught from undercooked meat, was at a decade high, while Campylobacter infections increased by 17% between 2023 and 2024 – from 60,055 to 70,352.

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While any improperly handled food can carry risks, certain summer staples are more likely to harbour harmful bacteria if they’re not stored or cooked correctly

Here’s what the everyday foods you should handle with care and the safest way to cook them.

1. Chicken

A UK-wide survey by the Food Standards Agency found that just over 5% of chicken we buy at the supermarket contains Salmonella.

While this number might sound alarming, Salmonella is usually killed when chicken is cooked thoroughly on a high heat (it’s when we undercook chicken that food poisoning most often happens).

To check if your bird is safe to eat, the Food Standards Agency recommends looking for the following visual cues:

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When you cut into the thickest part of the meat, the juices should run clear. For a whole chicken or other bird, the thickest part is the leg between the drumstick and the breast.

There should be no pink or fleshy meat, as this is a sign it is undercooked.

Cut the meat open with a clean knife to check it is steaming hot all the way through – you should see steam coming from the meat.

2. Bagged salad

When you’re short on time, grabbing a bag of Italian side salad can be an easy way to hit your five-a-day without needing to pull out the chopping board.

But few people realise that pre-mixed leafy greens can be a harbinger of bacteria, as the moist environment may accelerate the growth of bugs like Salmonella.

A study by the University of Leicester found that nutrient-rich sugars, proteins and minerals from the cut salad leaves can leach into the water in the bag, providing the perfect conditions for pathogens to develop.

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The research authors said that these bacterias can establish themselves so strongly that washing them alone isn’t enough to ensure safety.

However, you don’t need to skip the salad aisle altogether, and you can still safely enjoy bagged versions with your BBQs this summer. The researchers just recommend washing and consuming your salad on the day of purchase, rather than leaving it in the fridge to wilt.

3. Shellfish

Oysters, mussels, shrimp and clams can be staples of summer dining, but they can also be considered a high risk for food poisoning because they can contain harmful bacteria, viruses and toxins like norovirus.

Contaminated shellfish can also contain Vibrio, a bacteria that naturally lives in seawater that can lead to mild illness, including diarrhoea and vomiting. In rare cases, it can lead to a more severe infection called Vibrio vulniuficus, which can be fatal.

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In the UK, an estimated 12,000 to 14,000 people per year experience sickness and diarrhoea after eating seafood, usually from raw oysters.

If you want to lower your risk, the UKFSA recommends opting for thoroughly cooked shellfish, as grilling seafood on a high heat kills most harmful pathogens.

Avoiding raw or undercooked shellfish minimises your chances of contracting a nasty stomach bug – which is especially important if you have a weakened immune system, liver disease or other underlying health conditions.

If you’re cooking shellfish at home, make sure you buy it from a reputable fishmonger and store it in the fridge at the correct temperature before cooking thoroughly.

Oysters can contain Vibrio, a seawater bacteria that can make you sick. (Image: Getty)

4. Rice

Leftover rice can contain spores of a bacterium called Bacillus cereus, which can quickly multiply if left at room temperature.

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Generally, It’s safe to eat cooked rice if it has cooled down quickly, been stored in the fridge and eaten within 24 hours. That said, you should never reheat rice more than once.

To store cooked rice safely, you should:

Chill it as quickly as possible, ideally within one hour

Take it out of the rice cooker, steamer or pan to cool it down faster

Consider dividing it into smaller portions to cool it down more quickly

Once at room temperature, put it straight into the fridge

Don’t store it for longer than 24 hours before eating

Wondering about rice from your local takeaway? Some food businesses cook their rice and serve it to customers immediately, while others might precook and reheat it before serving. This means it can be hard to tell whether takeaway rice is safe to reheat or not.

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If in doubt, it’s always best to make a fresh portion at home, rather than risking your health.

5. Eggs

There are few things better in life than a perfectly poached egg on toast, but your favourite brekkie can also be a hidden source of Salmonella, especially if it’s eaten raw or undercooked.

Studies have found that Salmonella bacteria can harbour both on the eggshell and inside the egg itself. In the past, this made eating runny eggs a bit of a gamble, but most eggs now sold in UK supermarkets carry the British Lion mark. This means they come from hens vaccinated against Salmonella and are produced to strict hygiene standards.

If your eggs have the Lion mark, they’re generally safe to eat soft-boiled or poached – even for children, pregnant women and older adults. But if the eggs don’t have the Lion stamp, such as those bought from local farmer’s markets, you should take care to cook them thoroughly until both the white and yolk are firm.

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To stay extra safe:

Store eggs in the fridge and keep them away from strong-smelling foods

Check the use-by date before cracking

Wash hands and surfaces after handling raw eggs

Finally, avoid eating foods made with raw eggs, like homemade mayonnaise or protein shakes, unless you’re certain the eggs are British Lion quality.

Read more about food poisoning:

Even so, exposure calls surged in the first half of 2024, and they are starting to climb once again.

“We see one of these every day,” said Hannah Hays, medical director of the Central Ohio Poison Center and chief of toxicology at Nationwide Children’s Hospital. “Most of the cannabis poisonings in young children under 6 are edibles.”

Kids can get very sick from consuming cannabis, but Ohioans can help prevent this from happening by taking a few simple steps to safely store their stashes.

Edible sales

Many marijuana users get high from smoking the plant form of the substance or taking hits from vapes loaded with cartridges containing THC, which is the main psychoactive component of pot.

But THC edibles also are quite popular in Ohio, according to sales data from the Ohio Division of Cannabis Control.

Since recreational marijuana sales began a year ago, on Aug. 6, 2024, consumers across Ohio have purchased 4.2 million THC edibles, or $91 million worth of product.

Ohio now has 158 marijuana dispensaries, including seven in Montgomery County, five in Butler County, four in Warren County, two in Miami and Clark counties, and one in Greene County, according to data from the Division of Cannabis Control. Ohio’s dispensaries have sold more than $344 million worth of recreational marijuana plant products (104 million pounds) and $225 million worth of vape cartridges and oils.

There are all kinds of THC edibles, including cookies, brownies, chocolates, candies and gummies that come in lots of flavors. THC-infused sodas and drinks also are fairly popular and sold at quite a few local businesses.

Kids problems

Back in 2015, Ohio’s two Poison Centers (the Central Ohio Poison Center and the Cincinnati Drug and Poison Information Center) received only 11 calls about kids 5 and younger being exposed to THC edibles.

Five years later, in 2020, the centers handled 181 cannabis exposure calls. Calls increased 34% in 2021; 37% in 2022; and 24% in 2023.

Last year, the Poison Centers fielded 582 edible exposure calls involving young kids (up 41% from 2023).

In a podcast last year, Dr. Shan Yin, medical director of the Cincinnati Drug and Poison Information Center, said Ohio saw an increase in children ingesting cannabis edibles after medical marijuana was legalized in Ohio in 2016. He said he believed childhood exposures would increase because of the legalization of recreational pot.

Many THC edibles look virtually indistinguishable from products that do not contain the drug, especially when they are out of their packaging. And many kids have a sweet tooth and love to munch on candy, chocolates, cookies, brownies and other treats. Young kids also are naturally curious and often like to put things in their mouths.

THC edibles with adult dosages can be overpowering and dangerous for small kids, said Hays, with the Central Ohio Poison Center. Kids sometimes eat multiple edibles, she said, far more than an adult would knowingly choose to consume.

Hays said the effects of edibles can take 30 to 60 minutes to kick in, which means that children may consume large doses of THC before they or anyone realize they are displaying symptoms of a marijuana overdose.

Kids who consume cannabis often experience anxiety, dizziness, sleepiness and have slurred speech, Hays said. On rarer occasions, kids will have hallucinations, seizures or respiratory failure, and they can end up in a coma.

Accidental marijuana poisonings involving young kids are scary and upsetting to parents, family members and loved ones, who also may feel guilty and worry they might get into trouble, Hays said.

The experience can be very disturbing and distressing for kids and families, but children tend to recover very well after receiving supportive care, Hays said.

Poison center nurses and pharmacists typically instruct callers to take children who have ingested marijuana to the hospital for evaluation and treatment. But sometimes children can be monitored at home and don’t need to visit the emergency department.

Precautions

Adult Ohioans who purchase cannabis are responsible for storing it in a safe way that prevents young people from getting access, says the Division of Cannabis Control.

State officials recommend marijuana users keep their stashes in a safe or lockbox. Ohioans who provide cannabis to minors can face fines and possible jail time.

Marijuana edibles should be stored on high shelves or in hard-to-reach places that are separate from where normal food products are kept, Hays said. It’s generally a bad idea to keep THC products in a purse or handbag when there are children around or in the household.

Officials recommend labeling all marijuana edible products in the home, and they advise adult Ohioans not to eat edibles in front of children, who often mimic their behaviors.

Even though edible cannabis exposures involving young kids increased last year, the number of calls to the Ohio Poison Centers about these incidents declined for three consecutive quarters — in Q3 and Q4 of 2024, and in Q1 of 2025. The number of incidents rose again in Q2 of this year.

Hays said she does not know what explains the trend. But she said it’s possible there were fewer incidents because users switched from using unregulated and homemade edible cannabis products to products from dispensaries, which tend to have safer packaging.

Ohio law requires regulated edible marijuana products to have child-resistant packaging. Homemade edibles obviously are a different story.

Still, Hays said kids sometimes can get into packaging that is considered child resistant. She said it would be wise to use more secure storage containers.

The poison help line (1-800-222-1222) provides free and confidential advice to callers. Calls are answered by nurses and pharmacists with specialized training in poisonings. Officials recommend parents and adult family members save this number in their cell phones in case of emergencies.

DENVER — A new study, co-authored by a Denver Health research scientist, reveals a dramatic increase in pediatric fentanyl exposures in the U.S. between 2015 and 2023.

According to the study co-authored by Joshua Black, Ph.D, exposures rose by 924% in children 12 or younger and 1,506% in teenagers.

The study pulled data from more than 50 poison centers across 49 states and has shown that not only has there been an increase in poisonings, but the severity of these cases has worsened, with life-threatening exposures increasing from 16% in 2015 to nearly 45% in 2023.

According to Denver Health, over 5,000 children have died from fentanyl overdoses in the past two decades, with a significant spike during the first two years of the COVID-19 pandemic.

Denver Health

Denver Health said that the overwhelming majority of exposures for young children were unintentional. But among teens, it’s a different story. For 13- to 19-year-olds, it’s predominantly misused, with those children intentionally using it for some effect.

Black encourages families to have naloxone on hand and to know how to use it.

If you or someone you know has been exposed to a poison or toxin, call the Poison Help Line at 800-222-1222 or use poisonhelp.org to get immediate assistance. The Rocky Mountain Poison Center has provided 24-hour poison emergency service for more than 60 years.

North Carolina Poison Control received more than 1,100 cannabis-related calls, with 42% of them involving children under 13.

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CHARLOTTE, N.C. — North Carolina health officials are sounding the alarm about a significant increase in the number of cases of kids being exposed to cannabis.

Data released Monday by North Carolina Poison Control shows that the agency received more than 1,100 cannabis-related calls in 2024, with 42% of them involving a child under 13. That’s up dramatically from 2020 when North Carolina Poison Control managed 518 cannabis exposure calls, 27% of which involved a child under 13.

“We are concerned about the increase in cannabis cases among children over time that we’re seeing,” Dr. Michael Beuhler said. “Parents should know that a child can become sick after eating only one gummy.”

Officials say products like edibles can be especially dangerous to kids who can’t distinguish them from regular candy. Because kids have lower body weight than adults, they’re more likely to experience cannabis poisoning, which can cause several symptoms, including difficulty breathing. Other symptoms include slurred speech, weakness, severe fatigue, nausea and vomiting.

Of particular concern are cannabis products that closely resemble everyday candy and chocolate, making accidental consumption more likely. Not all products accurately label their cannabis content, further complicating the risk.

Beuhler strongly urges parents and caregivers to treat cannabis products with the same extreme caution as prescription medications. “Look at these as medication,” he said. “You wouldn’t leave your blood pressure medication out on the counter. This should be the same thing, and even more so, because it looks a lot like candy in some cases.”

“Cannabis-containing products should be stored securely away from children, just like medications,” Alexa Steverson, manager of communications and content development for North Carolina Poison Control, said. “Children can be enticed by appealing packaging and can easily mistake edible products for familiar foods and snacks.”

Officials also warned consumers that cannabis products may not always accurately list the amount of THC they contain, potentially increasing the risk of an overdose. Anyone who suspects a child may have consumed cannabis products should immediately contact NC Poison Control at 1-800-222-1222. The service is available 24 hours a day via phone and online.