From Plants to Pharmacy: The Natural Compounds Behind Modern Medicines

Last updated: October 2026.

Some of the most important medicines in history started life in a meadow, a forest or a mouldy Petri dish. Willow bark, foxglove, the opium poppy and humble fungi all gave scientists the starting point for drugs still used every day.

This article tells some of those stories. It also explains an important point that often gets lost online: the fact that a medicine came from a plant does not mean the plant itself, or any supplement, works the same way or is as safe.

The short answer

• Many important medicines were discovered in, or inspired by, plants and fungi, including aspirin, morphine, digoxin, quinine, penicillin and metformin.
• Scientists isolated, purified and tested specific compounds, and set precise doses, which is very different from taking the raw plant.
• “Natural” does not mean safe: foxglove and the opium poppy are a reminder that plants can be powerful and dangerous.
• Food supplements, including CBD, are not medicines and should never replace medication prescribed by your doctor.

Aspirin: from willow bark and meadowsweet

For thousands of years, people chewed willow bark or made teas from it. In the 1820s, scientists isolated a compound called salicin from willow, and later from meadowsweet, a plant that grows along Irish riverbanks and ditches. Salicin is converted in the body to salicylic acid, which works but is harsh on the stomach. In 1897, chemists at Bayer created acetylsalicylic acid, a modified version that was easier to tolerate. They named it aspirin, the “spir” coming from Spiraea, the old botanical name for meadowsweet.

Morphine: from the opium poppy

The opium poppy has been used for pain and sleep for millennia. In 1804, the German pharmacist Friedrich Sertürner isolated morphine, the first active compound ever purified from a plant. It remains one of the most important medicines for severe pain, but its history is also a stark lesson in dependence and harm.

Digoxin: from the foxglove

In 1785, the English physician William Withering published a study on foxglove, a plant familiar in Irish hedgerows, after learning of its use in a traditional remedy for “dropsy”, the swelling caused by heart failure. Compounds from foxglove led to digoxin, still used for some heart conditions. Foxglove is also highly poisonous: the difference between a helpful and a toxic amount is small, which is exactly why careful dosing matters.

Quinine: from cinchona bark

The bark of the South American cinchona tree was used to treat fevers and became the first effective treatment for malaria in Europe. Quinine was isolated in 1820. Today the tonic in your gin and tonic still contains a small amount, far below medicinal levels.

Penicillin: from a mould

In 1928, Alexander Fleming noticed that a mould, Penicillium, had killed bacteria growing on a plate in his laboratory. It took more than a decade, and the work of Howard Florey, Ernst Chain and their team, to turn this into a usable medicine. Antibiotics transformed medicine and have saved many millions of lives.

Metformin: from French lilac

Goat’s rue, also called French lilac, was used in medieval Europe for symptoms we now associate with diabetes. Its active compound, galegine, inspired the development of metformin, today one of the most widely prescribed medicines in the world for type 2 diabetes.

Artemisinin: from sweet wormwood

Chinese scientist Tu Youyou searched ancient texts and found references to sweet wormwood for fevers. Her team isolated artemisinin in the 1970s, which became a key malaria treatment. She received the Nobel Prize in Physiology or Medicine in 2015.

Statins and fungi

Statins, used to lower cholesterol, also trace back to fungi. The first statin was discovered by Japanese scientist Akira Endo in the 1970s from a Penicillium mould, and lovastatin was later isolated from Aspergillus terreus. Fungi also gave us ciclosporin, which helps prevent organ transplant rejection.

Medicine	Natural source	Year isolated or developed
Morphine	Opium poppy	1804
Quinine	Cinchona bark	1820
Aspirin	Willow bark and meadowsweet	1897
Digoxin	Foxglove	1930 (studied from 1785)
Penicillin	Penicillium mould	1928, mass-produced 1940s
Metformin	Goat’s rue (French lilac)	1950s (used clinically)
Artemisinin	Sweet wormwood	1972

How a medicine is developed today

The path from a promising natural compound to a medicine on a pharmacy shelf is long. It usually takes more than a decade and passes through several stages:

• Discovery. Researchers screen thousands of compounds, natural or synthetic, for activity against a target.
• Laboratory and animal studies. Promising compounds are tested for how they work and whether they are safe enough to try in people.
• Phase 1 trials. Small numbers of healthy volunteers help establish safety and dosing.
• Phase 2 trials. Larger groups of patients test whether the compound works and continue to monitor safety.
• Phase 3 trials. Hundreds or thousands of patients, usually compared with placebo or an existing treatment.
• Regulatory review. In Ireland, medicines are authorised by the HPRA or through the European Medicines Agency.
• Ongoing monitoring. Side effects continue to be tracked after the medicine is on the market.

Only a small fraction of compounds that enter trials ever become approved medicines. That is why a single laboratory study on a plant extract, however exciting the headline, is a long way from proof that it works in people.

Irish hedgerows: beautiful, but handle with care

Ireland’s hedgerows hold several plants with a medical history, including meadowsweet, foxglove and willow. Many traditional Irish remedies used local plants. It is a rich heritage worth celebrating, but foraging for medicinal use is risky: plants can be misidentified, potency varies hugely, and some, like foxglove, are toxic in small amounts. Enjoy them on a walk, and leave the medicine-making to the professionals.

What this does and does not mean

These stories are remarkable, but they are often used online to suggest that “natural” remedies are better than medicines. That is the wrong lesson. In every case above:

• Scientists identified a specific active compound.
• They purified it and often modified it to make it safer or more effective.
• They worked out a precise, reliable dose.
• The medicine was tested in clinical trials and is now regulated.

Chewing willow bark is not the same as taking a measured aspirin, and eating foxglove is dangerous. “Natural” and “safe” are not the same thing.

Where does CBD fit?

CBD is a compound from the hemp plant that is also the subject of active medical research. One purified CBD medicine is licensed in Europe as a prescription medicine for certain rare forms of childhood epilepsy, prescribed only by specialists. That is a very different product from the CBD food supplements sold in shops and online, which are not medicines, are not licensed to treat any condition, and should never be used in place of prescribed medication.

At Dr. Hemp Me we sell CBD as a food supplement for people who want to include it in a general wellness routine, such as our CBD Oil 10% and CBD Gummies. We are fascinated by the science, but we are clear about the limits. Learn more about how CBD interacts with the body in the hidden system inside you, and about the research on functional mushrooms in our mushroom guide.

The future of plant and fungal medicine

Scientists continue to screen plants, fungi and marine organisms for new medicines, particularly as antibiotic resistance grows. Biodiversity matters here: every species lost may be a medicine never discovered. It is a good reason to protect hedgerows, bogs and woodlands, including here in Ireland.

Frequently asked questions

Did aspirin come from a plant?

Yes. Aspirin was developed from salicin, a compound found in willow bark and meadowsweet.

Is natural medicine safer than pharmaceutical medicine?

Not necessarily. Many plants are powerful and some are toxic. Licensed medicines have tested doses and safety information.

Is CBD a medicine?

One purified CBD medicine is licensed for certain rare forms of epilepsy on prescription. CBD sold as a food supplement is not a medicine and cannot treat any condition.

Can I replace my medication with natural products?

No. Never stop or replace prescribed medication without speaking to your doctor.

Which medicines came from fungi?

Penicillin, the first statins and ciclosporin all trace back to fungi.

Is foxglove dangerous?

Yes, foxglove is highly poisonous. Never use it as a home remedy.

Are scientists still finding medicines in nature?

Yes. Plants, fungi and marine life are still screened for new compounds, especially new antibiotics.

How long does it take to develop a new medicine?

Usually more than ten years, from discovery through laboratory work, three phases of clinical trials and regulatory review.

Who approves medicines in Ireland?

The Health Products Regulatory Authority (HPRA), or the European Medicines Agency for medicines authorised across the EU.

Is it safe to forage for medicinal plants?

It is risky. Plants are easily misidentified, potency varies and some, like foxglove, are toxic. Do not use foraged plants as medicine.

Disclaimer: CBD is sold as a food supplement. It is not intended to diagnose, treat, cure or prevent any disease and is not a substitute for medical advice. Always consult a healthcare professional before starting a new supplement, especially if you take medication, are pregnant or breastfeeding.