Nature makes both medicine and deadly poison, and respecting it means telling them apart

Key takeaways

• A 2019 study of nearly 20,000 adults in England linked at least two hours a week in nature with better health and well-being, though it could not prove cause and effect.
• Foxglove and willow bark led to the heart drug digitalis and to aspirin, but only after people learned to measure and purify them.
• The bacteria behind botulism live in soil worldwide, and USDA counts their toxin among the most toxic substances known.
• In 1900, about 100 of every 1,000 American babies died before age 1; by 2024 the rate was about 5.5 per 1,000, and the CDC credits much of the drop to clean water, sanitation, nutrition and medicine.
• Of 5,411 medicinal plants assessed by Kew scientists, 13% were threatened, so respecting nature also means protecting it.

In early December 2025, California’s public health director, Erica Pan, gave unusual advice: don’t forage for wild mushrooms at all this season¹.

As of December 7, 2025, when the Associated Press reported the warning, the state’s poison control system had identified 21 cases of amatoxin poisoning, most likely from death cap mushrooms. One adult had died, and several patients, including children, had severe liver damage¹.

Death caps look a lot like edible mushrooms. Cooking does not make them safe, and the early stomach symptoms can fade before liver damage shows up¹.

Yet the same woods and parks where those mushrooms grow are places where time outdoors is linked to better health. Both facts are true at once.

That tension sits at the heart of natural health. Respect for nature is wise. Idealizing nature, assuming that whatever is natural must be kind, pure or safe, is something else, and it can hurt the very people who love nature most.

“Natural” feels like a promise, but philosophers have long said it isn’t one

In 1874, an essay by the English philosopher John Stuart Mill, called simply “Nature,” was published². He pointed out that the word has two meanings. It can mean everything that exists, including us, or it can mean whatever happens without human interference².

Neither meaning, Mill argued, tells us how to live. In the first sense, nothing we do can be unnatural. In the second, nature includes hurricanes, plagues, starvation and poison².

He put it bluntly: “nearly all the things which men are hanged or imprisoned for doing to one another are nature’s every-day performances”². Our duty, he concluded, is to improve on nature, not to imitate it².

The shortcut Mill was attacking is often called the appeal to nature. It is the belief that something must be good or safe because it is natural.

Psychologists have measured how strong that pull is. A 2019 review led by Gettysburg College psychologist Brian Meier found that people favor “natural” options in food, medicine, beauty products and even cigarettes and lighting, even when the natural version is identical or no better³.

In experiments by the same team, about 86% and 93% of participants in two studies chose a natural pain reliever over a synthetic one when offered a free gift⁴. The choice tracked a belief that natural meant safer and more effective. A short explanation that natural and synthetic drugs can each be good or bad shrank the bias⁴.

The preference is not foolish. It may reflect healthy caution about the new and a wish for things made with care. The fix is to treat “natural” as a reason to start asking questions, not a reason to stop.

Two hours a week in nature is linked to better health

Here is where respect for nature pays off. A 2019 study in Scientific Reports looked at 19,806 adults in England. People who spent at least 120 minutes a week in natural settings were more likely to report good health and high well-being than people who spent no time there⁵.

Less than two hours showed no clear link. The benefits leveled off at around 200 to 300 minutes a week⁵.

It didn’t matter whether the two hours came in one long outing or several short ones. The pattern held for adults over 65 and for people with long-term illness or disability⁵.

The authors were careful about the limits. The survey was a single snapshot, so healthier people may simply get outside more. Time in nature explained only about 1% of the differences in health, and exercise may account for part of the link⁵.

That makes nature time promising but early as medicine. Still, few health habits are this cheap, this pleasant and this low in risk.

Some of medicine’s oldest drugs came from plants, after people learned to measure

In 1775, the English physician William Withering was asked about a family remedy for dropsy, the old name for fluid swelling. An old woman in Shropshire had kept the recipe secret, and it blended 20 or more herbs. He concluded that foxglove was doing the work⁶.

His 1785 book is a lesson in humility. He admitted that at first he gave doses that were far too large, for far too long⁶.

He also described a traveling Yorkshire tradesman whose wife stewed a big handful of fresh foxglove leaves for him. The man drank it all at once, vomited without stopping, and his pulse fell to 40 beats a minute. He barely survived⁶.

So Withering standardized. He picked leaves only when the plant was in bloom, dried and later powdered them, and gave measured doses, stopping once nausea or heavy urine flow began. He also reported every case, including the failures and the deaths⁶.

The plant’s active substance was later identified and purified, and digitalis became a cornerstone of heart failure treatment for generations⁷. Today, newer drugs have largely replaced it, though it still has a small role⁷.

Willow bark tells a similar story. People in ancient Mesopotamia, Egypt, Greece and Rome used it as medicine. An English clergyman, Edward Stone, reported its use in 50 patients to the Royal Society in 1763⁷.

Johann Buchner, a scientist in Munich, isolated its active compound, salicin, in 1828. Bayer, after working on a version with fewer side effects, began selling aspirin in 1899 to relieve pain and fever⁷.

Nature supplied the starting point. Careful measurement made it safe enough to use. Respecting a plant medicine means respecting its dose.

Nature also makes some of the deadliest poisons known

The bacteria that cause botulism, Clostridium botulinum, live as dormant spores in soil and seafloor sediments worldwide⁸. The U.S. Department of Agriculture calls their toxin among the most toxic substances known. Even microscopic amounts can sicken or kill⁸.

The spores turn dangerous in low-oxygen, low-acid conditions. That is why the CDC lists improperly home-canned, preserved or fermented foods as a common source⁹. USDA’s list of risky foods includes garlic stored in oil, baked potatoes sealed in foil, and traditionally prepared salted or fermented fish⁸.

Here is the twist. The same toxin, purified and measured, is injected for cosmetic and medical uses, and too large a dose can itself cause botulism⁹. Poison and medicine can be the same substance at different doses.

Molds can be just as deadly. In Kenya in 2004, families ate homegrown maize that had been stored damp after a harvest during heavy rains. By July 20, the outbreak had caused 317 cases of aflatoxin poisoning and 125 deaths, a 39% death rate¹⁰.

Aflatoxins are made by two species of Aspergillus mold. High doses can cause severe liver injury and death, and long-term, low-level exposure raises the risk of liver cancer¹⁰. CDC investigators recommended teaching safe drying and storage using methods that fit local culture¹⁰.

Wild mushrooms belong on this list, too. In 2023, U.S. poison centers logged more than 4,500 exposures to unidentified mushrooms, roughly half in young children¹.

Even a walk in the woods carries some risk. More than 80,000 Lyme disease cases are reported to the CDC each year. An estimate based on insurance claims suggests about 476,000 people are treated for Lyme each year. The CDC says that may run high, because billing codes don’t always reflect a confirmed diagnosis¹¹.

Before clean water, a “natural” life was often a short one

It is tempting to picture life before modern industry as healthier. The records tell a harder story. In 1900, pneumonia, tuberculosis, diarrheal disease and diphtheria caused one-third of all U.S. deaths, and about 40% of those deaths were in children under 5¹².

That year, about 100 of every 1,000 American babies died before their first birthday. Between 6 and 9 mothers died for every 1,000 births¹³. By 2024, infant deaths had fallen to about 5.5 per 1,000¹⁴.

The CDC credits much of that change to sewage systems, safe drinking water, chlorination beginning in the early 1900s, better nutrition, pasteurized milk and, later, antibiotics¹²¹³. U.S. life expectancy rose 29.2 years over the 20th century¹² and reached 79.0 years in 2024¹⁴.

Notice what most of those advances did. They shielded people from nature’s microbes, often by cleaning up crowded towns and cities. That is Mill’s argument in practice: improving on nature, carefully, is how families stopped burying so many babies.

Respect also means protecting what nature gives

Respect runs both ways. In 2020, 210 scientists from 42 countries contributed to a report from the Royal Botanic Gardens, Kew. It estimated that 39.4% of the world’s plant species are at risk of extinction¹⁵.

The report documented 25,791 plants used as medicine. Of the 5,411 assessed for conservation status, 723, or 13%, were threatened¹⁵. In South Africa, overharvesting of wild medicinal plants is a major worry: the number of species traded fell from 700 in 1998 to 350 in 2013¹⁵.

How a plant is harvested matters. When people dig up bulbs and roots or strip bark, the plant dies about 86% of the time¹⁵.

This is where natural-health values shine. People who care about plants are well placed to ask where an herb came from, choose cultivated sources and leave fragile wild stands alone. Our published article on white sage shows how one popular plant became a target for poachers.

Respect or idealize? A side-by-side guide

Use this table to catch yourself when admiration slides into assumption.

Situation	Idealizing says	Respecting says
Wild mushrooms	Found in a forest, so it must be pure	Eat only what an expert has identified; when unsure, throw it out
Herbal remedies	Plants are gentle	Plants contain real drugs; dose, timing and interactions matter
Home canning and fermenting	The old ways are always safest	Use tested recipes and pressure-can low-acid foods
Time outdoors	Nature cures everything	About two hours a week is linked to feeling better; it adds to care rather than replacing it
Hiking and gardening	Nature is harmless	Check for ticks and learn your area’s poisonous plants
Wild-harvested herbs	Wild is always best	Wild harvest can wipe out slow-growing plants; cultivated may be kinder
Lab-made medicine	Synthetic means worse	Aspirin was developed from willow’s chemistry to cut side effects; judge by evidence, not origin
Clean water and sanitation	Modern systems are unnatural	They helped cut infant deaths by more than 90%; keep them1314

Before you trust anything because it is natural, run it through five questions:

1. What exactly is it? Name the species, the part used and how it was prepared.
2. How much, and how often? Foxglove taught medicine that dose decides between help and harm.
3. What does the evidence say? Look for human studies, not just tradition or testimonials.
4. Who could be hurt? Think about children, pregnancy, older adults and anyone taking medicines.
5. What does it cost the land? Ask whether it was grown, gathered sustainably or stripped from the wild.

What the evidence says

Claim	Evidence rating	What the research shows
Regular time in nature supports health and well-being	Promising but early	Large survey link; cause not proven5
Purified plant compounds can make effective medicines	Strong evidence	Digitalis and aspirin became standard drugs7
Natural substances are safe because they are natural	Evidence says no	Botulinum toxin, aflatoxin and amatoxin are all natural1810
Cooking makes poisonous mushrooms safe	Evidence says no	Health officials warn cooking does not help1
Clean water and sanitation reduced child deaths	Strong evidence	Century-long CDC records1213
People prefer “natural” even when products are identical	Promising but early	Consistent findings in a young field34
Wild harvesting threatens some medicinal plants	Strong evidence for assessed species	13% of assessed medicinal plants threatened15

Questions readers ask

The bottom line

Natural health is right to honor nature. Time outdoors is linked to better well-being, and plants gave medicine some of its oldest and most important drugs.

Honor is not the same as trust without questions. Nature also makes botulinum toxin, aflatoxin and death caps, and life before clean water was hard on children. Respect means learning from nature, protecting it and judging each of its gifts one at a time.

Related reading

• How to appreciate white sage without taking, since yours may have been poached
• How to judge a cup of herbal tea, which is gentle but not automatically harmless
• Why “natural” on a food label guarantees almost nothing
• Community gardens passed a rare scientific test, so test the soil too
• Three better questions to ask than whether something is natural or synthetic

Sources

1. ABC7 News / Associated Press. “1 Killed, More Than 20 Poisoned by Death Cap Mushrooms in California, Officials Say.” ABC7 San Francisco, December 7, 2025. abc7news.com
2. Mill JS. “Nature.” In Nature, The Utility of Religion and Theism, 1874. Text hosted by Lancaster University. lancaster.ac.uk
3. Meier BP, Dillard AJ, Lappas CM. “Naturally Better? A Review of the Natural-is-Better Bias.” Social and Personality Psychology Compass, 2019;13(8):e12494. cupola.gettysburg.edu
4. Meier BP, Dillard AJ, Osorio E, Lappas CM. “A Behavioral Confirmation and Reduction of the Natural versus Synthetic Drug Bias.” Medical Decision Making, 2019. cupola.gettysburg.edu
5. White MP, Alcock I, Grellier J, et al. “Spending at Least 120 Minutes a Week in Nature Is Associated With Good Health and Wellbeing.” Scientific Reports, 2019;9:7730. nature.com
6. Withering W. An Account of the Foxglove and Some of Its Medical Uses, 1785. Project Gutenberg. gutenberg.org
7. Smulyan H. “The History of Three Ageless Cardiac Drugs: Aspirin, Digitalis, Nitroglycerine.” Upstate Medical University, 2020.
8. U.S. Department of Agriculture, Food Safety and Inspection Service. “Clostridium botulinum.” USDA FSIS, 2010. fsis.usda.gov
9. Centers for Disease Control and Prevention. “About Botulism.” CDC, updated 2026. cdc.gov
10. Centers for Disease Control and Prevention. “Outbreak of Aflatoxin Poisoning, Eastern and Central Provinces, Kenya, January–July 2004.” Morbidity and Mortality Weekly Report, 2004. cdc.gov
11. Centers for Disease Control and Prevention. “Lyme Disease Facts and Stats.” CDC, updated 2026. cdc.gov
12. Centers for Disease Control and Prevention. “Achievements in Public Health, 1900–1999: Control of Infectious Diseases.” Morbidity and Mortality Weekly Report, 1999. cdc.gov
13. Centers for Disease Control and Prevention. “Achievements in Public Health, 1900–1999: Healthier Mothers and Babies.” Morbidity and Mortality Weekly Report, 1999. cdc.gov
14. Xu J, Murphy SL, Kochanek KD, Arias E. “Mortality in the United States, 2024.” NCHS Data Brief No. 548, National Center for Health Statistics, 2026. cdc.gov
15. Royal Botanic Gardens, Kew. “State of the World’s Plants and Fungi 2020” (press release). Kew, 2020. kew.org