Medicinal plants: list, benefits, and proper use

Evening herbal tea, bud extract drops, capsules bought at the pharmacy: medicinal plants are part of many of our daily lives. But between advice from your neighbor, viral videos, and protocols found online, it's hard to know what really works, and above all, what is safe. To clear things up, we asked all our questions to Kelly Colonges, a PhD in plant biology, herbalist, and founder of La Réserve de l'Écureuil, a brand of supplements she makes from plants harvested in the Alpes-de-Haute-Provence.

Her message can be summed up in one sentence: plants have enormous potential, but they should never be taken lightly.

What is a medicinal plant?

A medicinal plant is a plant where one or more parts (flowers, leaves, roots, buds) contain active ingredients capable of acting on our body. For millennia, it was the only medicine available: before chemistry and pharmaceuticals, we treated ourselves with plants.

Kelly reminds us of a point we often forget: plants do not produce these molecules to heal us. They produce them to survive. A plant cannot move: if it is in direct sunlight, it cannot go find shade. It therefore manufactures compounds to protect itself from the sun, defend itself against insects, or attract pollinators. It is this potential that we harness.

How do we know if a plant has an effect?

It's impossible to tell with the naked eye. "If you're walking in the forest, you can't just say: that one is orange, so it must be an anxiolytic," Kelly says with a smile. Two approaches complement each other:

• Traditional use : the way plants have been used for centuries, passed down and documented. This is the foundation of herbalism.
• Biochemical analysis : the plant is ground up, its active ingredients are extracted, and then they are compared to molecules with known effects. This discipline is called pharmacognosy, and it follows the same process used to develop pharmaceutical drugs.

An increasing number of scientific studies are now validating traditional uses. This does not mean that every plant has been proven effective for every use: the level of evidence varies significantly from one plant to another.

The different forms of medicinal plants

The same plant can be taken in very different forms, known as galenic forms. They do not extract the same active ingredients, and they are not all subject to the same regulations.

Gemmotherapy was developed in the 1950s by Dr. Pol Henry. Kelly remains faithful to his original recipe (water, alcohol, and glycerin), whereas some manufacturers replace the glycerin with honey: glycerin has the added advantage of being vegan. A bud is very fragile, and its harvesting window sometimes lasts only a few days: Kelly goes hiking with jars already filled with solvent so that the buds can be immersed immediately.

A dietary supplement is therefore not necessarily a capsule. Kelly sums it up simply: it is a product with a precise dosage to be taken throughout the day, whether it be two capsules, 30 drops, or two measuring spoons. In France, every supplement must be declared to the DGCCRF before it is placed on the market, and each new combination of plants requires a new declaration. For certain more delicate active ingredients, the authorities also require dosage results.

List of medicinal plants and their traditional uses

Here are the plants that Kelly talks about most often at the counter of her herbal shop. The uses mentioned are traditional uses : they do not replace a diagnosis or a treatment. And a plant that works for one woman will not necessarily work for her neighbor.

For stress and sleep

These are, by far, the topics that come up most often at the counter. Before giving advice, Kelly asks questions: do you have trouble falling asleep, or do you wake up during the night? For falling asleep, we tend to turn to so-called anxiolytic plants, which calm the nervous system. For nighttime awakenings, we look to so-called hypnotic plants, which promote deeper sleep.

• Linden bud (gemmotherapy), which Kelly calls "the sleep bud": a sedative and antispasmodic for the nervous system. The general recommendation: about fifteen drops in a little water, about an hour before bedtime, because for some people it provides a small boost of energy before calming them down. Not for children under 3 or during pregnancy.
• California poppy (tincture), our bestseller: both anxiolytic and hypnotic. It should only be taken in the evening, around 30 drops, as it can cause drowsiness. It contains alkaloids, so be sure to strictly follow the recommended dosage.

We cover everything in our article on herbs for sleep.

For digestion

This is Kelly's personal story. During her PhD, in the midst of the Covid pandemic and intense stress, she was diagnosed with irritable bowel syndrome. The only solution offered: painkillers and anti-reflux medication for life. At 26, she refused to accept this, enrolled in herbalism school, and found her own solutions to complement her medical care.

• Fig bud : traditionally indicated for issues linking stress, the nervous system, and digestion. Kelly still takes it daily.
• Walnut bud : traditionally used to help rebalance the gut flora, which is often compromised after months of digestive issues.

According to Kelly, these two buds are among the safer plants, with no particular contraindications. However, persistent digestive issues always warrant a medical check-up before you turn to herbal remedies.

For the cycle and women's health

• Raspberry bud : one of Kelly's top sellers for women's health. It is traditionally used to regulate the cycle and soothe period pain, and is often mentioned in relation to PCOS. It also has a so-called uterotonic effect, traditionally used after childbirth, so it is not recommended during pregnancy.
• Sage and hops : the classics for menopause and hot flashes. They contain phytoestrogens and are contraindicated if you have a history of hormone-dependent cancer. We explain everything in our article on phytoestrogens.
• Holy basil (tulsi) combined with sweet clover : the hormone-free protocol that Kelly developed for women who cannot take phytohormones. Tulsi is an adaptogen, and sweet clover is known for its effect on hot flashes. Sweet clover requires caution if you are taking anticoagulants.
• Apple bud : it is effective for hot flashes, but as a precaution, it is contraindicated in hormone-dependent situations. It is not yet known whether it contains phytohormones, but it appears to behave in the same way.

To learn more about menopause, read our article on plants for hot flashes.

The plant that requires the most caution

St. John's wort, traditionally used for mood, is one of the only plants mentioned on the package inserts of certain medications. It accelerates a liver mechanism that breaks down drugs, making them less effective. This is particularly the case with the pill. We have a full article dedicated to it: St. John's wort: benefits and interactions.

The plants on this list are not suitable for everyone. If you are pregnant, breastfeeding, a child, currently undergoing treatment, or have a history of cancer, always seek the advice of a healthcare professional before taking them.

Are medicinal plants risk-free?

This is probably the most important message of the episode: no. "We tend to say that because it's natural, it's safe. In reality, there are quite a few plants that have contraindications or can interact with medications," insists Kelly.

ANSES agrees. In an opinion published to better inform consumers, the agency points out that plant-based supplements are not risk-free, and it has listed the precautions, contraindications, and potential interactions for 118 medicinal plants.

The main risks to be aware of:

• Contraindications : plants containing phytoestrogens are not suitable for those with a history of hormone-dependent cancer or hormonal diseases.
• Interactions with medications : St. John's wort is the best-known example, but not the only one. Read our article on medicinal plants and medications.
• Dosage : some plants, such as the California poppy, contain compounds that become toxic in high doses.
• Specific situations : pregnancy, breastfeeding, and children under 3 years old, particularly for extracts that contain alcohol.
• Protocols found online : Kelly often sees protocols brought to the counter that come from websites or AI, which are sometimes completely absurd and potentially dangerous.

Kelly adds a golden rule: never replace a medication with a plant, and be wary of anyone who advises you to do so. Plants and medications are not mutually exclusive: when used correctly, they can complement each other. In fact, Kelly works with a pharmacist and a health center.

How to choose a plant-based supplement

Always seek advice

"You shouldn't choose a plant extract on your own," Kelly replies without hesitation. Every plant has its own specific properties, and good advice starts with asking questions. For a sleep issue, for example, she first asks for your stress level on a scale of 1 to 10: often, "not too stressed" turns out to be a 7 or 8.

When faced with a protocol found online, her reflex is always the same: ask where the recommendation came from, then go over things together.

Look at labels, but don't treat them as a guarantee

Several labels can help you: Organic farming, Nature & Progrès, or membership in the Syndicat des Simples for small-scale producers. But be careful: organic certification primarily guarantees traceability and farming methods, not the concentration of active ingredients. An organic product is not necessarily more effective. Kelly recommends prioritizing small producers, and even better if they are certified.

Trust your senses

This is Kelly's most surprising tip: taste a drop of your extract pure, without water. Many active ingredients are also aromatic. A freshly prepared raspberry bud extract tastes like the fruit. If all the bottles from a brand taste roughly the same, it is sometimes a sign of processing that has altered the active ingredients (freezing, long delays between harvest and maceration).

Prioritize freshness and manufacturing rigor

For gemmotherapy, the window for picking a bud sometimes lasts only a few days, and every hour counts between harvesting and maceration. The laboratory's rigor also matters: Kelly has kept her researcher's habits, using a light-protected room for macerations and laboratory pipettes precise to the hundredth of a milliliter. This level of demand isn't always visible on the label, but you can ask the producer about it.

Who can advise you on plants?

Your pharmacist, your doctor, or an herbalist shop where the team is trained in contraindications and drug interactions. In fact, Kelly only works with these types of herbalists. She doesn't sell her extracts in organic stores yet: she is first preparing synergies that are easier to recommend for less specialized teams. A good indicator of the importance of professional advice.

Discover the episode with Kelly Colonges

In her Reflet 100% Naturel episode, Kelly shares how she went from a thesis on cocoa aromas to wild harvesting in the Alpes-de-Haute-Provence, and offers her advice for sleep, the menstrual cycle, and menopause.

To learn more, check out our content on the cycle and on menopause.

Key takeaways

• Medicinal plants contain active ingredients; their effectiveness is based on traditional use, which is increasingly being validated by science.
• Whether it's herbal tea, gemmotherapy, tinctures, or capsules, the form changes which active ingredients are extracted and how the product is regulated.
• Linden and California poppy for sleep, fig and walnut for digestion, raspberry leaf for the menstrual cycle: each plant has its own specific uses and precautions.
• Natural does not mean risk-free: contraindications, interactions, and dosages all matter.
• You should never choose a plant on your own, and you should never replace medication with a plant.

FAQ

What are the most commonly used medicinal plants?

Some of the most common in herbalism include: linden and California poppy for sleep, fig and walnut for digestion, raspberry leaf for the menstrual cycle, sage for menopause, and St. John's wort for mood. Each has its own specific precautions for use.

Are medicinal plants safe?

No. Some plants have contraindications (such as pregnancy or a history of hormone-dependent cancer) or interact with medications. Seek advice from a healthcare professional before taking them.

Does a plant-based dietary supplement always come in a capsule?

No. A dietary supplement is defined by a precise daily dosage. It can come in the form of drops, capsules, or powder.

Is organic certification a guarantee of effectiveness?

Not on its own. The organic label guarantees the farming method and traceability, but not the quantity of active ingredients in the final product.

Can you replace medication with a plant?

No. Never stop a treatment to replace it with a plant without your doctor's advice. However, plants and medications can complement each other when used under professional guidance.

The information in this article is for educational purposes only and does not replace professional medical advice. Kelly Colonges holds a PhD in plant biology and is an herbalist; she is not a healthcare professional. Before taking any plants, especially if you are pregnant, breastfeeding, currently undergoing treatment, or have a medical history, consult your doctor or pharmacist.