Herbs have been used in traditional healing systems for thousands of years, and many familiar plants still appear today in teas, capsules, extracts, essential oils, and other products marketed for health and wellness.
But “natural” does not automatically mean safe, and centuries of traditional use do not necessarily prove that an herb treats a particular medical condition.
Modern research paints a much more interesting—and nuanced—picture. Some herbs have evidence supporting specific uses. Others look promising but need better studies. In some cases, the form of the herb matters enormously: drinking peppermint tea, for example, is not equivalent to taking an enteric-coated peppermint-oil capsule studied for irritable bowel syndrome.
Herbal supplements can also cause side effects, interact with medications, and be inappropriate during pregnancy, breastfeeding, childhood, or before surgery. In the United States, dietary supplements are not approved by the FDA for safety and effectiveness before they are sold in the same way medications are.
That does not mean herbs have no place in wellness. It means they deserve the same thoughtful approach we would give any biologically active substance.
Here are seven popular medicinal herbs, what researchers currently know about them, and the safety considerations worth understanding before you use them.
🌸 1. Echinacea
Echinacea is one of the most recognizable medicinal plants in North America. Its pink-purple flowers are common in gardens, while extracts of Echinacea purpurea, Echinacea angustifolia, and related species appear in teas, tinctures, tablets, capsules, and cold-season supplements.
Native American peoples used echinacea medicinally long before the plant became commercially popular. Today, it is most frequently promoted as an immune-support supplement and a way to prevent or shorten the common cold.
Research offers a much more modest conclusion.
According to the National Center for Complementary and Integrative Health, taking echinacea may slightly reduce the likelihood of catching a cold, but researchers still do not know whether it reliably shortens how long a cold lasts.
That distinction matters. Echinacea should not be treated as a proven cold cure, nor is there good evidence that it broadly “boosts” the immune system in a way that protects against every infection.
Different echinacea products can also vary substantially. They may use different plant species, different parts of the plant, different extraction methods, and different concentrations, making research results difficult to compare.
For most adults, certain echinacea preparations appear reasonably safe when used for short periods. Digestive symptoms such as stomach discomfort and nausea can occur.
Allergic reactions are a more significant concern. Echinacea belongs to the daisy family, and some people may experience severe allergic reactions. Anyone with significant plant allergies or who takes prescription medication should discuss concentrated echinacea supplements with a health professional before using them.
What the evidence suggests: Echinacea may provide a small preventive benefit against the common cold, but evidence that it shortens an established cold remains uncertain.
🫚 2. Ginger
Ginger (Zingiber officinale) occupies an unusual position because it is both an everyday culinary ingredient and one of the better-studied herbal remedies.
The part we commonly call ginger root is technically a rhizome, an underground stem. Fresh ginger, dried ginger, tea, powders, extracts, and capsules have all been used in traditional medicine and modern herbal products.
Of ginger’s many promoted benefits, nausea is one of the best studied.
Research suggests that ginger may help reduce nausea and vomiting associated with pregnancy. Studies have generally examined supplemental ginger preparations rather than ordinary amounts used to season food.
That does not mean every kind of nausea responds to ginger. Research on motion sickness has mostly failed to demonstrate a clear benefit, while evidence for nausea following surgery or during chemotherapy remains uncertain.
Ginger supplements may also help reduce the severity of menstrual cramps. There is some research on ginger for osteoarthritis symptoms as well, but study quality has often been limited.
In culinary amounts, ginger is widely consumed. More concentrated oral products can cause heartburn, abdominal discomfort, diarrhea, or irritation of the mouth and throat.
Anyone taking medication should be cautious about assuming concentrated ginger supplements are automatically compatible with it. Pregnancy is another situation where discussing supplements with a clinician is sensible even though ginger has been studied for pregnancy-related nausea.
There is an important difference between adding grated ginger to dinner, drinking a mild ginger tea, and regularly taking a concentrated extract.
What the evidence suggests: Ginger has reasonable evidence for pregnancy-related nausea and some evidence for menstrual cramps, but many other popular claims remain uncertain.
💛 3. Turmeric
Turmeric (Curcuma longa) is another familiar kitchen spice that has become enormously popular in the supplement aisle.
The bright yellow-orange rhizome belongs to the ginger family and has a long history in South Asian cooking as well as traditional medical systems, including Ayurveda.
Much of the modern interest in turmeric centers on curcumin, one of a group of compounds called curcuminoids that contribute to turmeric’s characteristic color.
You may have encountered claims that turmeric can treat inflammation, arthritis, depression, digestive problems, heart disease, cancer, or practically any other condition imaginable.
The evidence is much less sweeping.
Studies of turmeric and curcumin for knee osteoarthritis have produced encouraging preliminary results, including possible reductions in pain and stiffness. Researchers still need higher-quality evidence before drawing firm conclusions, however.
Turmeric and curcumin have also been studied for conditions including fatty liver disease and treatment-related mouth inflammation, but the evidence is not strong enough to conclude that they provide reliable benefits across these conditions.
One reason turmeric research is difficult to interpret is that products differ dramatically.
Curcumin is not absorbed particularly well by the body. Some manufacturers therefore create “high-bioavailability” formulas, sometimes combining curcumin with ingredients such as piperine from black pepper.
Greater absorption may sound automatically beneficial, but it can change the safety profile too.
Cases of liver injury have been reported with some highly bioavailable turmeric or curcumin supplements. Symptoms that could indicate liver problems—including dark urine, jaundice, unusual fatigue, nausea, or poor appetite—require prompt medical attention.
Turmeric used normally as a culinary spice is very different from swallowing concentrated curcumin supplements every day.
Supplemental turmeric can also cause stomach upset, reflux, diarrhea, nausea, or constipation. Medicinal-dose supplements may be unsafe during pregnancy.
What the evidence suggests: Turmeric and curcumin show promising early evidence for some osteoarthritis symptoms, but claims that turmeric broadly treats inflammation or numerous chronic diseases go well beyond current evidence.
🌼 4. St. John’s Wort
St. John’s wort (Hypericum perforatum) deserves a different level of caution from most herbs on this list.
Its yellow flowers have a long history of traditional medicinal use, and modern supplements are most commonly marketed for depression and mood.
Research suggests that standardized St. John’s wort extracts may help some people with mild to moderate depression, and studies have sometimes found effects comparable with standard antidepressant medications over relatively short treatment periods.
That finding can make St. John’s wort sound like a simple “natural antidepressant.”
It isn’t.
St. John’s wort is one of the clearest examples of why an herbal product can be pharmacologically active enough to help in one situation and dangerous in another.
It interacts with many medications.
St. John’s wort can accelerate processes the body uses to break down medicines, potentially reducing their concentrations and making them less effective. Documented concerns include certain birth control pills, antidepressants, anti-seizure drugs, transplant medications such as cyclosporine, heart medicines, HIV medications, cancer treatments, warfarin, and some cholesterol-lowering statins.
Combining St. John’s wort with certain antidepressants or other substances that increase serotonin can also raise the risk of serious serotonin-related side effects.
It may increase sensitivity to sunlight and can cause dizziness, digestive symptoms, restlessness, difficulty sleeping, and other adverse effects.
In the United States, St. John’s wort is not FDA-approved as a treatment for depression.
Depression can also be a serious medical condition requiring appropriate assessment and care. Someone already taking an antidepressant should not stop it or replace it with St. John’s wort without medical guidance.
Of all the herbs in this article, this is the one that most clearly demonstrates why a pharmacist or clinician should know what supplements you are taking.
What the evidence suggests: St. John’s wort may help some cases of mild to moderate depression, but its extensive and potentially serious medication interactions make self-treatment risky.
🌼 5. Chamomile
Chamomile has one of the gentlest reputations in the herbal world.
A warm cup of chamomile tea is practically shorthand for relaxation and bedtime, and the herb has been used historically for digestive discomfort, anxiety, skin conditions, colds, and sleep.
Several plants are called chamomile. Research commonly focuses on German chamomile (Matricaria chamomilla or Matricaria recutita).
Despite chamomile’s enormous popularity, high-quality evidence for many of its promoted medicinal uses remains limited.
Preliminary research suggests that concentrated chamomile supplements may help some people with generalized anxiety disorder, but larger and more definitive studies are still needed.
Evidence for insomnia is surprisingly weak. Although chamomile tea is commonly associated with sleep, research has not established it as a reliable treatment for insomnia.
That does not mean enjoying chamomile tea before bed is pointless. A warm caffeine-free drink can be part of a pleasant evening routine. It simply means we should distinguish the comfort of the ritual from evidence that chamomile itself treats a sleep disorder.
Chamomile tea in ordinary food amounts is generally considered safe for most people.
Allergic reactions can occur, however, and may occasionally be severe. Risk can be higher among people allergic to plants in the same family, including ragweed, chrysanthemums, marigolds, and daisies.
Chamomile may also interact with medications. Reported or suspected interactions include the blood thinner warfarin and potentially sedating drugs.
Safety during pregnancy and breastfeeding has not been well established.
What the evidence suggests: Chamomile has some preliminary evidence for anxiety, but there is not strong evidence that it treats insomnia or the many other conditions frequently attributed to it.
💜 6. Lavender
Lavender (Lavandula angustifolia) may be best known for its fragrance.
The aromatic plant is used in soaps, perfumes, bath products, teas, culinary preparations, essential oils, and supplements. It is particularly associated with relaxation, sleep, stress relief, and anxiety.
Here, the form of lavender matters enormously.
Research on an oral standardized lavender-oil preparation has suggested that it might reduce symptoms of anxiety in some people. However, studies have limitations, and additional independent, high-quality research is needed.
That finding should not be interpreted as evidence that people should swallow ordinary bottles of lavender essential oil.
A product formulated and studied for oral use is not interchangeable with an essential oil sold for fragrance or topical aromatherapy.
Lavender aromatherapy is enormously popular, but evidence that inhaled lavender reliably treats anxiety, depression, pain, insomnia, or other health conditions remains uncertain. Some people nevertheless report that they enjoy the scent and find lavender aromatherapy relaxing.
There is nothing wrong with enjoying an aroma because you find it pleasant. The key is not converting personal preference into an unsupported medical claim.
Lavender used in ordinary food amounts is generally considered safe. Oral products may cause headache, nausea, diarrhea, or burping. Inhaled lavender can sometimes provoke headache or coughing, and topical lavender products may cause allergic skin reactions.
Researchers also have limited information about lavender safety during pregnancy and breastfeeding, and there are theoretical concerns about combining concentrated lavender products with sedating medications or herbs.
What the evidence suggests: A specific oral lavender-oil preparation has shown promise for anxiety, but evidence for many aromatherapy claims—including reliable treatment of insomnia—is still inconclusive.
🌿 7. Peppermint
Peppermint (Mentha × piperita) is a natural hybrid of water mint and spearmint and is one of the world’s most familiar aromatic herbs.
The leaves are used in food and tea, while peppermint essential oil contains highly concentrated aromatic compounds, including menthol.
Like lavender, peppermint illustrates why we need to pay attention to which preparation researchers actually studied.
Peppermint tea is commonly enjoyed after meals, but most of the stronger clinical research has focused on enteric-coated peppermint-oil capsules, particularly for irritable bowel syndrome.
Research suggests that enteric-coated peppermint oil can improve overall IBS symptoms and reduce abdominal pain in some adults. The American College of Gastroenterology has also recommended peppermint oil as one option for relief of overall IBS symptoms.
Enteric coating allows the capsule to travel farther through the digestive tract before releasing the oil and may help reduce some upper-digestive side effects.
Peppermint oil can still cause heartburn, indigestion, nausea, abdominal discomfort, or dry mouth.
This evidence does not mean that peppermint tea has been proven to treat IBS. Very little research has examined peppermint leaf itself for specific medical conditions.
Essential oil also requires particular caution around young children. Menthol-containing peppermint oil should not be applied to or inhaled close to the face of an infant or small child because of potential effects on breathing.
And as with other concentrated essential oils, a bottle intended for aromatherapy should not automatically be assumed safe for swallowing.
What the evidence suggests: Enteric-coated peppermint-oil capsules have some of the better evidence among herbal products for reducing IBS symptoms in adults. Evidence for peppermint leaf or tea as a medical treatment is much more limited.
🌱 Herbal Tea Isn’t the Same as an Herbal Supplement
One of the easiest mistakes to make when reading about medicinal herbs is treating every form of a plant as equivalent.
They are not.
A cup of chamomile tea may contain very different concentrations of plant compounds than a standardized chamomile extract used in a research study.
A teaspoon of turmeric in curry is very different from a high-bioavailability curcumin capsule.
Peppermint leaves steeped in water are not equivalent to enteric-coated peppermint oil.
Lavender used to flavor a cookie is not equivalent to a concentrated oral lavender-oil product—and neither is equivalent to an essential oil placed in a diffuser.
Whenever you encounter a health claim about an herb, ask a crucial question:
What form was actually studied?
That single question can eliminate a surprising amount of misleading health advice.
💊 Natural Doesn’t Mean Free of Drug Interactions
Plants contain biologically active chemicals. That is one of the reasons people became interested in using them medicinally in the first place.
It is also why herbs can interact with medications.
St. John’s wort provides the clearest example, but it is not the only herb capable of causing interactions.
The risk can become particularly important for people taking blood thinners, transplant medications, seizure medicines, antidepressants, cancer treatments, heart medicines, or other drugs where changes in blood concentration can have serious consequences.
If you take prescription or over-the-counter medication regularly, a pharmacist can be an excellent person to ask about potential supplement interactions.
Bring the exact product name and ingredient list rather than simply saying you take “some herbs.”
🏷️ Herbal Supplements Aren’t Approved Like Medicines
Another important difference involves regulation.
In the United States, the FDA does not approve dietary supplements for safety and effectiveness before they are marketed in the same way it approves medications.
Manufacturers are responsible for ensuring that their products meet applicable safety and labeling requirements, while the FDA can take action against unsafe or improperly marketed products after they reach the market.
This means a supplement sitting on a store shelf has not necessarily demonstrated that it works for the health condition advertised around it.
Products sold under the same herb name may also differ in species, plant part, extraction method, concentration, added ingredients, and dosage.
That helps explain why a clinical trial using one standardized extract cannot automatically validate every bottle containing the same herb.
🤰 Be Especially Careful During Pregnancy and Breastfeeding
Pregnancy is not a good time to assume that an herb must be safe because it comes from a plant.
Many herbal supplements have never been adequately tested during pregnancy or breastfeeding.
Others contain concentrations far exceeding what someone would normally encounter in food.
Ginger has some research supporting its use for pregnancy-related nausea, but even then it is sensible to discuss supplemental doses with a prenatal health professional.
Medicinal-dose turmeric may be unsafe during pregnancy. St. John’s wort raises additional concerns. Safety information for herbs such as lavender and chamomile is incomplete.
Food amounts and concentrated medicinal supplements are not always equivalent.
👧 Herbs and Children Require Extra Care
Children are not simply smaller adults.
Their bodies process substances differently, and the safety information available for many herbal products is limited.
Concentrated essential oils are a particular concern.
Menthol-containing peppermint oil, for example, should not be placed on or close to the face of an infant or small child because it can interfere with breathing.
Echinacea has been studied in children to some extent, but allergic rashes have occurred, and NCCIH recommends talking with a child’s health care provider before giving a child an echinacea product.
Unless a product has appropriate safety information and dosing for children, do not assume an adult herbal remedy can simply be scaled down.
🩺 When to Talk With a Health Professional
You do not need a medical appointment every time you sprinkle turmeric on roasted vegetables or make a cup of peppermint tea.
Concentrated supplements deserve more consideration.
Talk with a doctor, pharmacist, or other appropriate health professional before regularly using an herbal supplement if you take medications, have a chronic health condition, are preparing for surgery, are pregnant or breastfeeding, or are considering giving the supplement to a child.
Medical symptoms that are persistent, severe, unexplained, or worsening also deserve proper assessment rather than repeated attempts to manage them with home remedies.
Herbs can sometimes complement conventional care.
They should not become a reason to postpone care that you need.
🌿 A More Realistic Way to Think About Medicinal Herbs
Herbal medicine becomes much more interesting when we move beyond the idea that plants are either miraculous cures or useless folklore.
Reality sits somewhere in between.
Ginger has evidence for some kinds of nausea. Enteric-coated peppermint oil can help some adults with IBS. St. John’s wort appears capable of affecting depression symptoms—but it also interacts with an extraordinary number of medications. Echinacea may provide a modest preventive benefit against colds. Turmeric research is promising in some areas but far less conclusive than advertising often implies.
Chamomile and lavender remind us that an herb can still be enjoyable even when every traditional claim has not been scientifically established.
You can drink chamomile tea because you enjoy the ritual.
You can grow lavender because it smells wonderful.
You can cook with turmeric and ginger because they taste good.
Not every plant needs to become medicine.
And when you do use an herb medicinally, the most useful questions are straightforward: What was actually studied? How strong is the evidence? What form was used? What are the side effects? Could it interact with anything else I’m taking?
Those questions make natural health considerably less mysterious—and considerably safer.
🔗 Related Articles
- Starting Your Own Herb Garden: A Beginner’s Guide to Culinary and Medicinal Delights
- How to Brew the Perfect Cup of Tea
- Step-by-Step Guide to Making the Perfect Golden Milk Recipe
- Lemon Balm Tea: Melissa officinalis
📚 Sources & Further Reading
- National Center for Complementary and Integrative Health — Echinacea
- National Center for Complementary and Integrative Health — Ginger
- National Center for Complementary and Integrative Health — Turmeric
- National Center for Complementary and Integrative Health — St. John’s Wort
- National Center for Complementary and Integrative Health — Chamomile
- National Center for Complementary and Integrative Health — Lavender
- National Center for Complementary and Integrative Health — Peppermint Oil
- National Center for Complementary and Integrative Health — Using Dietary Supplements Wisely
- National Center for Complementary and Integrative Health — How Herbs Can Interact With Medicines
- U.S. Food and Drug Administration — Information for Consumers on Using Dietary Supplements
