The poison without an antidote (and Part 4)

What became of Gramoxone (paraquat), the herbicide that reigned as the world’s best-seller for decades, yet earned the grim nickname “the poison without an antidote”? Did it vanish from the market? Does it still linger despite everything? Let’s take a look.

Paraquat (1,1’-dimethyl-4,4’-bipyridylium) was first synthesized by the British multinational ICI in 1882, but its properties as a contact herbicide weren’t discovered until 1955. After years of testing to assess its usefulness and applications, it hit the market in 1961 under the brand name Gramoxone. Its formula contained 200 grams of paraquat per liter of water, later supplemented with an emetic to mitigate the risks of accidental or intentional ingestion. As previously noted, it was applied by spraying 200 to 600 cc per 100 liters of water.
 
For decades, it brought success to farmers worldwide, boosting crop yields and quality. But its dangers gradually tarnished its reputation. In 2007, the European Union, including Spain, banned it. In countries with looser regulations, like China, it remained on sale until 2011, when it too was prohibited. But was that the end everywhere? Are there still places where it’s available?
 
The answer is yes. Though banned in the United Kingdom, the European Union, and many other nations, the UK continues to manufacture and export it to countries where laws permit its use. Some experts argue that in those regions, the risks of paraquat are deemed preferable to the threat of famine. Its effectiveness has never been questioned, even if its safety leaves much to be desired.
 
This is the story of the herbicide that led the market for decades and became as familiar to farmers as a hoe or any other everyday farming tool.
 

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The poison without an antidote (Part 3)

It wasn’t unusual to see farmers spraying the multipurpose herbicide Gramoxone (paraquat) without proper protection, nor was it surprising that accidents happened every year. Contact with paraquat, even when diluted in water, caused caustic injuries to mucous membranes, while its absorption could severely damage the lungs, liver, kidneys, and heart. These weren’t minor risks—they could be significant, even deadly. That’s why ICI altered its formula, adding an emetic—a substance that induces vomiting—to minimize the time the product remained in contact with internal mucous membranes during accidental ingestion.

Yet negligence persisted. Every year, there were examples, some as shocking as a farmer who, after using a Gramoxone container, washed it and repurposed it as a water bottle. It happened more than once. And despite the washing, traces of paraquat’s toxicity lingered, landing that reckless farmer in the hospital in varying degrees of severity.
 
There was more. Though less common, suicides also occurred. Seeing the “poison” label on the container, some chose to drink it. This was a different beast altogether, and I certainly wouldn’t recommend it as a suicide method. There are faster, less painful options. Drinking paraquat, even just a sip, tears apart the internal tissues it touches. The emetic might trigger vomiting, but the damage is already done. At the hospital, there’s no specific antidote; the only option is a thorough gastric lavage, followed by a tube delivering a solution of one liter containing 150 g of Fuller’s earth in suspension and 20% mannitol. That’s it. And, of course, pray.
 
Such was Gramoxone (paraquat), the world’s most widely used herbicide, marketed for farmers to apply “on any weed, at any time, anywhere.” It was easily accessible to anyone.
 
But over the years, accidents, lack of protection, and overconfidence earned it the nickname “the poison without an antidote.” Many years have passed since then, and you might wonder: “What’s become of it?”
 
(To be continued…)
 

A journey through the history of the pharmaceutical industry and one of its great laboratories that had its origins in Alfred Nobel...
“From Alfred Nobel to AstraZeneca”: https://a.co/d/9svRTuI

The poison without an antidote (Part 2)

Gramoxone (paraquat) was a herbicide that, once applied (by spraying it onto the weeds we wanted to eliminate), dried them out with remarkable speed. It didn’t matter what kind of weed it was—Gramoxone was what’s known as a “total herbicide” and a “contact herbicide,” meaning it dried out anything it touched… as long as it was green. That was one of its major advantages: it only affected the green parts of plants (disrupting photosynthesis and killing the plant) and had no impact on non-chlorophyll-producing parts like trunks, branches, or roots. This meant there was no issue if the spray reached tree trunks during application—it wouldn’t harm them; it targeted only the green foliage. On the flip side, since it killed the green parts of weeds without affecting their roots, those weeds could regrow over time. But that wasn’t a problem either—you could simply spray them again and dry them out once more.
 
Those unfamiliar with agriculture might wonder, “Why would a farmer want to dry out weeds?” In the farming world, these plants are called “weeds”—not because they’re inherently bad, but because they grow where farmers don’t want them. Like all plants, weeds draw moisture and nutrients from the soil, competing with the crops that sustain the farmer’s livelihood. A field cleared of weeds allows crops to grow healthier and stronger, yielding more and better produce by eliminating those rival plants.
 
Gramoxone had other advantages too: it deactivated upon contact with soil, leaving no residue; it wasn’t volatile; and it worked effectively regardless of weather conditions or soil type. Its extreme versatility was evident in its many uses—it wasn’t just for drying weeds that competed with crops. It was also used to clear grass from rooftops, paved areas, and even along railway tracks across Spain, where a specialized company applied it to prevent overgrown weeds from posing a derailment risk. One of its most popular slogans captured this perfectly: “For any weed, at any time, in any place.” In short, it was a product every farmer kept on hand and used frequently.
 
It came in containers of 250 cc, 1 liter, and 5 liters as a soluble liquid. The recommended dilution was 400 to 600 cc per 100 liters of water. Once prepared, this mixture was sprayed onto the weeds and unwanted growth, taking care not to hit the green parts of the crops being protected. Naturally, it was emphasized that users should wear proper protective gear—overalls, gloves, and a mask—to ensure the spray didn’t contact their skin or lungs during application.
 
Trust and Risk
 
But I’ve used words like “care,” “protected,” and “protection”—words that stand in stark contrast to another: “familiarity.” And that’s where the trouble began. Gramoxone (paraquat) was so widely used by so many farmers that it had become almost too familiar—practically a member of the family. And with familiarity comes overconfidence, and with overconfidence… risks start to emerge.
(To be continued…)
 

A well-documented exploration of Medicine, Pharmacy, and rural society in the 19th century through two biographies that should not be forgotten:
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The poison without an antidote (Part 1)

Can you imagine a deadly poison with no antidote, one that anyone could easily and cheaply buy? Can you picture a lethal poison sold by the hundreds of thousands worldwide every year? Well, such a poison existed for decades, with hundreds of thousands of units sold annually, and it wasn’t until 2007 that its sale began to be banned in some countries. This is my story of working with that hugely successful commercial product: paraquat.

When I started my career in the agrochemical industry at the British multinational ICI (Imperial Chemical Industries) back in 1983, I was introduced to the company’s flagship product: Gramoxone. This herbicide, with paraquat as its active ingredient, was the company’s top seller globally, including in Spain, and within its category, it reigned as the most widely sold herbicide of all. As the Advertising Manager for the company, my job was to create advertising campaigns and organize promotions to ensure this product maintained its market dominance. With an advertising budget of around 200 million pesetas (equivalent to 1.2 million euros) in 1980s terms, Gramoxone claimed the lion’s share of those funds. I used it to launch major advertising campaigns and dazzling promotional events. That’s how I became intimately familiar with this product, as did countless farmers who were its primary customers—though, in truth, you didn’t need to be a farmer to buy it.
 
Anyone could purchase it freely at garden centers, nurseries, agricultural supply stores, and even at the company’s own retail shop on Ferraz Street in Madrid—the same street where the headquarters of the Spanish Socialist Party (PSOE) is located. That store was open to the public, and all sorts of people walked in to buy. Curiously, some spent more on insecticides or fungicides for the little plants in their balcony pots than the plants themselves were worth. It would’ve been cheaper to replace the plants than to buy products to fight their pests! What’s more, the insecticides, herbicides, fungicides, fertilizers, and other items sold in that shop were designed for agricultural use, with labels listing dosages per hectare, not per flowerpot.

(To be continued…)

A well-documented exploration of Medicine, Pharmacy, and rural society in the 19th century through two biographies that should not be forgotten:
“Kisses are tears”: https://a.co/d/eCok2Y0

Agrochemical products and “Safety Period”

The “safety period” refers to the minimum amount of time that must elapse between the application of an agrochemical product (such as an insecticide, fungicide, or herbicide) to a crop and the time of harvest. If the crop is harvested before this period has ended, toxic residues may remain on the produce, posing a risk of contaminated food reaching the market. However, if the harvest occurs after the safety period, any agrochemical residues on the crop will have dissipated or become inactive, allowing the produce to be sent to market with full safety assurances.

But why would any farmer consider harvesting before the safety period is complete? The answer lies in market demands: produce must be delivered at its peak ripeness. If the agrochemical was applied later than intended, farmers might feel pressured to harvest early—before the safety period ends—to avoid delivering overripe or poor-quality crops to the market. This is why it’s critical to clearly specify this information in promotional brochures, catalogs, and other materials, and why company sales representatives must explain it thoroughly during the regular meetings they hold with potential clients.

 

A journey through the history of the pharmaceutical industry and one of its great laboratories that had its origins in Alfred Nobel...
“From Alfred Nobel to AstraZeneca” (Vicente Fisac, Amazon) is available in e-Book and print editions: https://a.co/d/9svRTuI

A fungus that kills another fungus

Can a fungus kill another? And if so, how could that benefit us? This is the story of a discovery that transformed the world of fungicides used in agriculture to combat fungal diseases. It all began 55 years ago in the former Czechoslovakia…

In that country, two types of edible fungi—Oudemansiella mucida and Strobillurus tenacellus—were known to grow on decaying wood in forests. But until then, no one had noticed a curious detail: where these fungi thrived, no other fungi grew nearby.
 
It wasn’t until the 1970s that the reason became clear: these two fungi secreted a substance that killed any rival fungi daring to encroach on 'their territory,' potentially stealing moisture and nutrients. This natural fungicide, which harmed other fungi but not the ones producing it, was identified as betamethoxyacrylic acid. Scientists realized they had stumbled upon a promising breakthrough—here was a substance that could combat fungal attacks on agricultural crops. But it wouldn’t be that simple. The compound proved photochemically unstable and highly sensitive to temperature changes, making it impractical for commercial use.
 
Years later, in 1982, researchers at Zeneca Agrochemicals (now Syngenta) took this molecule apart and developed no fewer than 1,400 variants. Eventually, they created one that met the necessary conditions for effective agricultural use: azoxystrobin. Just seven years later—thanks to the compound’s excellent eco-toxicological profile—field trials began, demonstrating its ability to effectively fight fungal attacks across a wide range of crops without harming the plants or the environment.
 
Much like the natural fungicide secreted by those two fungi, azoxystrobin shared a similar mode of action, including a lack of resistance from target fungi. The molecule easily penetrated the cell walls of pathogenic fungi, reaching their mitochondria—the energy-producing organelles critical to fungal survival. By disrupting the electron transport chain, it halted ATP synthesis (the fungus’s vital energy source). Without energy, the fungus died, allowing the affected plant to resume normal growth.
 
Azoxystrobin revolutionized fungicides with unprecedented properties, becoming an essential ally in protecting crops worldwide. It offers preventive action (powerfully inhibiting spore germination and early fungal development) as well as curative and eradicative effects (remaining highly active against post-germination stages of various fungal species, whether applied before or after an infection).
 
Another standout feature is its exceptional toxicological and environmental profile. This was evident when it received its first registration in 1998 in Germany—a country known for its stringent Green movement standards. Just months later, the U.S. Environmental Protection Agency (EPA) granted its approval.
 
Rarely has an agrochemical company developed a product with such remarkable traits. This original, groundbreaking fungicide, with a mode of action unlike anything before it, proved effective against a broad spectrum of diseases—including downy mildew, powdery mildew, excoriosis, black rot, Alternaria, anthracnose, and Septoria—in over 60 commercially significant crops.
 
Today, azoxystrobin is no longer exclusive to one company; it’s marketed by numerous agrochemical firms under various trade names and concentrations, tailored to specific crops. But in its time, it was a true revolution that reshaped the world of agricultural fungicides.
 

A journey through the history of the pharmaceutical industry and one of its great laboratories that had its origins in Alfred Nobel...
“From Alfred Nobel to AstraZeneca” (Vicente Fisac, Amazon) is available in e-Book and print editions: https://a.co/d/9svRTuI