During the French Revolution, a botanist's letter asking about "dear Rhus" (poison ivy) was intercepted and led to authorities' suspicions he was conspiring with the Russians

During the French Revolution, a botanist's letter asking about "dear Rhus" (poison ivy) was intercepted, leading authorities to suspect he was conspiring with the Russians.

Poison ivy was sent to Europe in the 1600s as an exotic, ornamental oddity

The plants were grown in the English royal gardens at Kew, the Faculty of Medicine in Paris, and a few other locations.

Poison ivy was sent to Europe in the 1600s as an exotic, ornamental oddity, where it was purposefully grown in the English royal gardens at Kew, the Faculty of Medicine in Paris, and a few other locations.

Poison ivy's rash-causing compound is found in the plant's roots, stem, and leaves—so coming into contact with any part of the plant can lead to rashes for the 85% of people who are allergic to it.

Poison ivy's rash-causing compound is found in the plant's roots, stem, and leaves—so coming into contact with any part of the plant can lead to rashes for the 85% of people who are allergic to it

Once sold as an ornamental plant, poison ivy can actually look varied—its colors change seasonally from reddish to green to yellow. It typically has three broad, shiny, tear-shaped leaves. But it sometimes may have a different number of leaves, and its edges can be serrated.

Scientists testing how climate change affects plants found, in a years-long simulation study, that poison ivy grew 70% faster with the resulting extra carbon dioxide.

Poison frogs get their toxins from eating insects and mice

Other animals, including royal ground snakes, are able to survive eating poison. Scientists study the creative antitoxin defenses in these animals to discover treatments for poisoning.

The story of the Radium Girls, who exposed the dangers of radioactive paint

After radium was discovered in 1898, companies began using radium-based paints on watch and clock dials to create a glow-in-the-dark effect. Women who worked to apply the paint were encouraged to use their lips and tongues to help create the fine point needed to draw small numbers, unknowingly poisoning themselves.

Rome's herbal panacea may not be as extinct as we thought

Silphion: cure-all, aphrodisiac, birth control, tasty seasoning. Nero allegedly ate the last of this miracle plant. This article details how a researcher may have found more. Seven centuries after the yellow-flowered plant was first documented growing in what's now Libya, it vanished. Historians proposed that the loss of Silphion may have been the first recorded extinction of any species.

Hippocratic doctors treated severe mental illness with the poisonous plant hellebore

Since symptoms like hallucinations were believed be due to an imbalance of black bile, yellow bile, blood, and phlegm, the treatment at the time was to bring those humors back into balance. That meant standard treatments could include bleeding a patient or using substances like hellebore to induce vomiting or diarrhea.

In 1951, a small French town was overtaken by the fungus that ultimately led to LSD

During the summer of 1951, the French town of Pont-Saint-Esprit appeared to go mad. Hundreds were treated for hallucinations and delirium, with some reporting ongoing hallucinations a month after the LSD-like symptoms appeared. Some historians argue it was a case of ergotism, better known in the Middle Ages as "burning disease" and "St. Anthony's Fire."

Teddy Roosevelt was given a daily dose of saccharin

America's 26th president was prescribed a sugar-free diet by his clinician, so when the chief chemist for the US Department of Agriculture approached him with concerns about the product's safety in the early 1900s, the duo clashed over how to regulate it.

The expedition documented 240 plant species, 178 new to western science

Lewis and Clark’s botanical records introduced species to Americans like bitterroot, ponderosa pine, and Oregon grape—plants unknown to western science at the time. See a selection of these species in this image gallery.

The legacy of Agent Orange: a photo gallery

An herbicide sprayed over the Vietnamese jungles during the war had a far greater impact than its supposed role as a defoliant, a chemical used to remove greenery. Agent Orange’s deleterious nature quickly impacted exposed people – and their children. This photo gallery, which includes graphic images, follows a photographer as they report on those affected by the chemical.

Who was behind the fatal 1982 Tylenol poisonings?

In 1982, an unknown suspect laced Tylenol packages with potassium cyanide in a Chicago pharmacy. Seven people were killed, and the case led to a nationwide panic, as well as the development of tamper-resistant packaging. No one was ever charged with the deaths, and the lead suspect died in 2023 after serving time in prison for trying to extort $1 million from a manufacturer to "stop the killing."

A history of treating frostbite

Amid Napoleon's invasion of bitterly cold Russia, soldiers succumbed to frostbite by the thousands. Nineteenth century doctors recommended walking and rubbing snow around the affected area. Fast forward to recent years, and the FDA has approved its first ever drug to treat frostbite. Listen to this podcast to learn the history of this wintry affliction.

Diphtheria was once a leading childhood killer before antibiotics and vaccines

In 18th- and 19th-century outbreaks, some New England families lost as many as eight children to diphtheria, and fatality rates in hospitals often topped 60%. The invention of antitoxins, penicillin, and vaccines dramatically reduced deaths.

Watch an expert's take on the rare disease hantavirus—and why it's not of great concern to the general population

This rare zoonotic disease, transmitted to humans primarily through infected rodent droppings, urine, or saliva, is rarely spread between people. The disease was of particular concern in spring 2026, when an outbreak occurred on a 150-person cruise ship, prompting a flurry of action, including contact tracing for passengers in their home countries. The disease can be fatal. But early care—primarily oxygen support—can help patients survive.

Allergies occur when our immune system mistakenly considers a substance a threat

Immunoglobulin E antibodies, or IgE antibodies, may bind to an allergen, effectively labeling it as a threat. That triggers a cascade of actions in the body, including the release of histamine, which causes the characteristic itching and hives of allergies. Sometimes a cooked version of an allergen—like a cooked carrot—may look different enough from its raw form to the immune system that antibodies ignore it, and no allergic response takes place.

Listen to an in-depth conversation on the links between Parkinson's disease and herbicide exposure and the challenging pace of scientific investigation.

Symptoms of DNA loss may mimic those seen in mushroom poisoning or chemotherapy

Although no organism has ever lost all its DNA, the destroying angel mushroom contains amatoxin, which disrupts DNA transcription and is known to cause death via liver and kidney failure in three days. Doxorubicin, which tangles DNA to disrupt cellular replication, compromises a person's immune system.

Listen to an in-depth conversation on the links between Parkinson's disease and herbicide exposure

This podcast takes on the thorny mismatch between recent research linking herbicide exposure to Parkinson's disease and federal and state regulators' conclusions that there is insufficient evidence to establish causality. Though the main company that produces the herbicide Paraquat has recently stopped making it, dozens of others continue to do so, prompting concerns from some Parkinson's patients and scientists about disease risk and the pace of scientific answers. 

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

How slugs helped soldiers during WWI

Slimy, squishy, slow-moving, and heroic? Slugs are land-dwelling mollusks known mostly for causing havoc in our gardens. But during World War I, slugs saved numerous soldier's lives as poison gas detectors. Learn how the unpleasant creatures earned their stripes in the battle to protect soldiers from chlorine, phosgene, and mustard gas as organic detectors.

A history of raising the alarm, from rattles to 911

Because fires spread so quickly, communities around the world have deployed many tactics to raise the alarm to get help. This history from the Museum of Natural History dives into the use of rattles, bells, and brigades to gather help to fight fires, showing just how far we've come since 911 was introduced in 1968.

The research pipelines being explored by the RIPE Project to improve photosynthesis

These include engineering plants with faster stomata, which would allow photosynthesis to resume more quickly amid fluctuations in available light due to clouds or shading from other plants, and resolving bottlenecks in the regeneration of RuBP, the molecule to which carbon dioxide is fixed during photosynthesis to initiate the Calvin cycle. (Some readers may experience a paywall.)

Lupus, an autoimmune disease with varied symptoms, was named for wolf bite-like lesions

The 13th-century physician behind the name (lupus is Latin for wolf) named it after a patient he saw who had facial lesions that looked to him like a wolf's bite. Other common symptoms of the disease include extreme fatigue, painful and swollen joints, fevers, and light sensitivity.

Well before the publication of 'Walden,' Henry David Thoreau nearly burned down his hometown

On April 30, 1844, the transcendentalist set a campfire that quickly grew out of control, burning 300 acres of woods near Concord, Massachusetts. For years, Thoreau remarked that other residents called him the "woods burner." Thoreau, though, felt no guilt, writing in 1850, "It has never troubled me from that day to this more than if the lightning had done it."

Kava, kratom, St. John's Wort, and green tea extract present health concerns

Consumer Reports, which tests supplements for safety, urges consumers to avoid these four supplements due to safety warnings from researchers and public health authorities.

Sunflowers have long been a symbol of nuclear disarmament because they can extract large amounts of radioactive cesium from soil.

Do trees feel pain?

Trees don’t have nerves or brains. But when they’re wounded, they send underground and airborne warnings to other trees.

Human-to-human transmission of hantavirus remains extremely rare, so the 2026 hantavirus cruise ship outbreak doesn't mean we're facing a COVID-style pandemic risk.

The use of fungi to detoxify land and water—a process known as mycoremediation—has been used to clean up natural resources affected by the 2025 California wildfires.

When a Paris department store hesitated to sell Estée Lauder's perfume, she 'accidentally' broke a bottle, causing the smell to spread throughout the store and shoppers to start asking to buy the scent.

Before writing 'Walden,' transcendentalist Henry David Thoreau nearly burned down his hometown with a campfire that grew out of control.

Louisiana's 'Cancer Alley' is infamous for having some of the highest industrial pollution, toxic air emissions, and cancer risks in the US.

Many legends about George Washington, including his supposed wooden teeth and the story of cutting down the cherry tree, lack evidence.

Sunflowers have long been a symbol of nuclear disarmament because they can extract large amounts of radioactive cesium from soil.

Volcanic activity may have triggered the Black Death by spewing gases that led to crop failures in Europe, thus forcing the import of grain ships with plague-infested fleas.

See images of medical cases of firework injuries shared on this 'Instagram for doctors.' (Warning: Graphic content)

The 19th-century painters of the Hudson River School were among the first American romantics, with portraits that displayed the natural beauty of the young country.

Ebola species have historically been named after where they were discovered, stigmatizing residents who live there, including Bundibugyo, in Uganda.

US intelligence allegedly pursued more than 600 schemes to assassinate Cuban revolutionary Fidel Castro.

Abraham Lincoln was almost assassinated weeks before his inauguration as he traveled from Illinois to DC through Baltimore in 1861; it took two independent claims for Lincoln to be convinced the threat was real

Coral reefs get their colors from zooxanthellae—microorganisms that line corals' digestive tracts and provide them with sugars in exchange for a home within this protective tissue.

Doctors differentiate between a phobia and fear by asking patients whether their fear interferes with their day-to-day activities.

The rivalry between Alexander Hamilton and Thomas Jefferson centered on federalism—the question of how much power the federal government should hold relative to the states.

Prince's sexually explicit 1984 track 'Darling Nikki' attracted the ire of the Parents Music Resource Center, an advocacy group that inspired the Parental Advisory sticker, even though the song ends with a Christian message.

The term 'algorithm' originated from the Latinized name of al-Khwārizmī, a 9th-century mathematician whose works introduced Arabic numerals and the decimal-based numeral system to Europe and whose treatise 'Al-Jabr' gave algebra its name.

For centuries, Niagara Falls has been a magnet for daredevils seeking to conquer one of nature's most powerful wonders, with its 200-foot drop and water rushing at 32 feet per second with 280 tons of force.