The tea tree, which is native to Australia, produces an oil that’s long been thought to be beneficial for skin conditions, including mild acne, athlete’s foot, small wounds, dandruff, insect bites, and other inflammatory skin conditions.
- Health Conditions
- Discover
- Plan
- Connect

Subscribe

# Nature’s 9 Most Powerful Medicinal Plants and the Science Behind Them



Medically reviewed by Debra Rose Wilson, Ph.D., MSN, R.N., IBCLC, AHN-BC, CHT — Written by Shelby Deering —  Updated on February 28, 2019



## We scoured through histories of herbal studies for you

Today, we live in a time when manufactured medicines and prescriptions prevail, but do they have to be the only approach to healing?

Even with all of these engineered options at our fingertips, many people find themselves turning back to the medicinal plants that started it all: Herbal remedies that have the ability to heal and boost physical and mental well-being.

In fact, at the beginning of the 21st century, 11 percent of the 252 drugs considered “basic and essential” by the World Health Organization were “exclusively of flowering plant origin.” Drugs like codeine, quinine, and morphine all contain plant-derived ingredients.

While these manufactured drugs have certainly become paramount in our lives, it can be comforting to know that the power of nature is on our side, and these herbal choices are available to complement our health practices.

But the extent of the power they hold is also still being explored. These alternatives aren’t cure-alls, and they aren’t perfect. Many carry the same risks and side effects as manufactured medicines. Many of them are sold with unfounded promises.

However, many herbs and teas offer harmless subtle ways to improve your health. Pay attention to what the evidence says about each herb’s effectiveness as well as potential interactions or safety issues. Avoid using herbs for infants and children and for those who are pregnant and breastfeeding. Most herbs haven’t been tested for safety for those who are vulnerable, and trying herbs isn’t worth the risk.

With this cautionary tale in mind, choosing the right plant can seem difficult to someone who simply wants to feel better without taking medication. That’s why, with the help of specialist Debra Rose Wilson, we’re looking at the most effective and therapeutic plants — which have strong scientific evidence to support their safe use.

Making decisions about herbs along with more traditional medicinal approaches is something you and your healthcare practitioner can address together. At times, Wilson notes, ingesting the plants can have even less risk than taking concentrated, manufactured supplements, as there’s more risk of contamination of the product with the manufacture processes. It’s a wonderful way to experience their effects and the satisfaction of growing them yourself. Herbs can also be a way to add a needed nutrient.

However, both plants and supplements, which aren’t regulated by the Food and Drug Administration for safety or quality, can have questionable dosage and might have a risk of contamination. Keep this in mind before choosing supplements from the shelf.

If you’d like to add some medicinal plants to your wellness regimen, Wilson sifted through the latest studies and provides her own ratings system for our list.

These plants have the most numerous high-quality studies and are the safer choices among herbal remedies. She’s marked “0” as unsafe with no research, and “5” as completely safe with ample research. Many of these plants are somewhere between 3 and 4, according to Wilson.

We hope this guide will act as a starting point to those who wish to integrate herbal remedies into their lives and arrive armed with knowledge. As always, speak with your doctor before starting any new health treatment.

## Gingko



### Rating

Safety: 3/5

Evidence: 3.5/5

As one of the oldest tree species, gingko is also one of the oldest homeopathic plants and a key herb in Chinese medicine. The leaves are used to create capsules, tablets, and extracts, and when dried, can be consumed as a tea.

Recent research is looking into a component that can help diabetes, and there continue to be more studies, including an animal study that says it might influence bone healing.

### Gingko could be beneficial for:

- dementia
- Alzheimer’s disease
- eye health
- inflammation
- diabetes
- bone healing
- anxiety
- depression

### Things to consider

- Long-term use may increase chance of thyroid and liver cancer, which has been seen in rats.
- It’s known to be hard on the liver, so liver enzymes may need to be monitored.
- It can interact with blood thinners.
- Gingko seeds are poisonous if ingested.
- Side effects can include headache, upset stomach, dizziness, and allergic reaction.
- Gingko use needs to be discussed with your doctor because of numerous drug interactions.

## Turmeric

### Rating

Safety: used as an herb: 5/5; used as a supplement: 4/5

Evidence: 3/5

With its brilliant orange hue, it’s impossible to miss a bottle of turmeric sitting on a spice shelf. Originating in India, turmeric is believed to have anticancer properties and can prevent DNA mutations.

As an anti-inflammatory, it can be taken as a supplement and it’s been used topically for people with arthritis who wish to relieve discomfort. It’s used worldwide as a cooking ingredient, which makes it a delicious, antioxidant-rich addition to many dishes.

### Turmeric could be beneficial for:

- pain caused by inflammatory diseases, like arthritis
- preventing cancer
- stopping DNA mutations
- several skin diseases

### Things to consider

- When used as a supplement, people tend to take too much, so it can be difficult to trust the dosage and quality. Safety increases when ingested as an herb in cooking or tea.
- Long-term use can potentially cause stomach problems.
- Turmeric has low bioavailability. Consuming with pepper can help your body absorb more of its benefits.

## Evening primrose oil

### Rating

Safety: topically: 4.5/5; orally: 3/5

Evidence: 3/5

The vibrant yellow evening primrose flower produces an oil that’s thought to alleviate the symptoms of PMS and skin conditions like eczema.

Studies that are available on this oil tend to be all over the map, but there are studies that are stronger than others. For example, some studies have found that evening primrose oil has anti-inflammatory properties. It’s been known to help with conditions such as atopic dermatitis and diabetic neuropathy. It can also help with other health concerns, such as breast pain.

Recent research points to improving the quality of life for patients with multiple sclerosis, changing hormones and insulin sensitivity in those dealing with polycystic ovary syndrome, and using it topically to improve mild dermatitis.

According to these studies, evening primrose oil might just be the Swiss Army knife of the medicinal plant world. The caveat is that it can interact with several medications. More research is coming, and the applications are promising.

### Evening primrose oil could be beneficial for:

- PMS
- mild skin conditions
- breast pain
- menopause
- inflammation
- diabetic neuropathy
- multiple sclerosis
- PCOS
- blood pressure

### Things to consider

- interacts with some blood-clotting medications
- safety during pregnancy is uncertain
- may interfere with drug absorption during HIV treatment
- interacts with lithium for bipolar disorder
- long-term use may not be safe

## Flax seed

### Rating

Safety: 4.5/5

Evidence: 3.5/5

Flax seed, also available as an oil, is one of the safer choices among plant-based dietary supplements. Harvested for thousands of years, today flax seed is praised for its antioxidant activity and anti-inflammatory benefits.

Although more research needs to be done with human subjects, one study says that flax seed can help prevent colon cancer.

Another study cites that flax seed has the ability to reduce blood pressure. When consumed, it can even aid in reducing obesity. Many people add flax seed and flaxseed meal to oatmeal and smoothies, and it’s also available in the form of tablets, oil (which can be put into capsules), and flour.

The best way to add flax seed is through your diet. Sprinkle ground seeds on cereal or salad, cook in hot cereal, stew, homemade breads, or smoothies. Add flaxseed oil to salad dressing.

### Flax seed could be beneficial for:

- decreasing obesity
- regulating blood pressure
- preventing colon cancer
- inflammation
- hot flashes

### Things to consider

- Flax seed can affect estrogen production in women, especially if they have a history of cancer or are pregnant.
- Don’t eat raw or unripe flax seeds, as they can be toxic.

## Tea tree oil

### Rating

Safety: 4/5

Evidence: 3/5

The tea tree, which is native to Australia, produces an oil that’s long been thought to be beneficial for skin conditions, including mild acne, athlete’s foot, small wounds, dandruff, insect bites, and other inflammatory skin conditions.

There needs to be further study into acne and scalp use, but for now, there’s a degree of research into the antimicrobial superpowers of tea tree oil on wounds and topical infections.

One recent study said that tea tree oil slowed the growth of acne-causing microbes. It’s commonly used as a highly concentrated essential oil.

Wilson recommends that tea tree oil, as with all essential oils, should be diluted in a carrier oil. She adds that it often already comes diluted in a variety of skin care products and creams.

### Tea tree oil could be beneficial for:

- acne
- athlete’s foot
- cuts
- dandruff
- insect bites

### Things to consider

- Tea tree oil is poisonous if taken orally.
- Your skin could experience an allergic reaction.
- It may influence hormones.
- Long-term use isn’t recommended.

## Echinacea

### Rating

Safety: 4.5/5

Evidence: 3.5/5

Echinacea is a lot more than those pretty, purple coneflowers you see dotting gardens. These blooms have been used for centuries as medicine in the form of teas, juice, and extracts. Today, they can be taken as powders or supplements.

The best-known use of echinacea is to shorten symptoms of the common cold, but more studies are needed to verify this benefit and to understand how echinacea boosts immunity when a virus is present.

Generally, save a few potential side effects, echinacea is relatively safe. Even though it needs more testing, you can always choose to use it if you’re hoping to see your cold symptoms end more quickly.

### Echinacea could be beneficial for:

- colds
- immunity
- bronchitis
- upper respiratory infections

### Things to consider

- It can be tough on the digestive tract and upset the stomach.
- Allergic reactions are possible.

## Grapeseed extract

### Rating

Safety: 4.5/5

Evidence: 3.5/5

For years, grapeseed extract, which is available via liquid, tablets, or capsules, has been well-established and applauded for its antioxidant activity. It has potent health benefits, including lowering LDL (bad) cholesterol and reducing symptoms of poor circulation in the leg veins.

Studies are confirming that regular consumption of grapeseed extract has anticancer effects and seems to halt cancer cell growth.

### Grapeseed extract could be beneficial for:

- cancer
- lowering LDL (bad) cholesterol
- leg vein circulation
- edema
- blood pressure

### Things to consider

- Proceed with caution if you take blood thinners or blood pressure medications, or if you’re about to go in for surgery.
- It may reduce iron absorption.

## Lavender

### Rating

Safety: 4/5

Evidence: 3.5/5

If you experience anxiety, chances are that someone along the way has recommended that you use lavender essential oil, and for good reason. This aromatic, purple flower has a fairly strong standing among studies, which have mainly focused on its anti-anxiety capacities.

It’s proven to be soothing in a study conducted among dental patients, while another study confirmed that lavender can directly impact mood and cognitive performance. It’s also been commended for its sedative properties to help people get much-needed sleep.

Recently, it’s been discovered that lavender carries anti-inflammatory benefits as well. It’s most effective diluted and applied to the skin or used in aromatherapy, and it has few side effects.

### Lavender could be beneficial for:

- anxiety
- stress
- blood pressure
- migraine

### Things to consider

- It can cause skin irritation.
- It may disrupt hormones when applied undiluted.

## Chamomile

### Rating

Safety: 4/5

Evidence: 3.5/5

With flowers that resemble small daisies, chamomile is another medicinal plant that’s thought to have anti-anxiety properties. Most people know it because it’s a popular tea flavor (one review says that over 1 million cups per day are consumed around the world), but it can also be ingested through liquids, capsules, or tablets.

The calming powers of chamomile have been frequently studied, including a 2009 study that states chamomile is superior to taking a placebo when treating generalized anxiety disorder. One recent study confirmed it’s safe for long-term use, and another recent study looked beyond its use for anxiety and confirmed that it also shows potential in anticancer treatments.

### Chamomile could be beneficial for:

- anxiety
- stress
- insomnia
- cancer

### Things to consider

- It can cause allergic reactions. There’ve been reports of anaphylaxis.
- It can interact with blood thinners.

Shelby Deering is a lifestyle writer based in Madison, Wisconsin, with a master’s degree in journalism. She specializes in writing about wellness and for the past 14 years has contributed to national outlets including Prevention, Runner’s World, Well+Good, and more. When she’s not writing, you’ll find her meditating, searching for new organic beauty products, or exploring local trails with her husband and corgi, Ginger.

### How we reviewed this article:

Sources

History

Healthline has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical journals and associations. We only use quality, credible sources to ensure content accuracy and integrity. You can learn more about how we ensure our content is accurate and current by reading our editorial policy.

- Badri O, et al. (2017). Combination therapy using evening primrose oil and electrical stimulation to improve nerve function following a crush injury of sciatic nerve in male rats. DOI:

- Chung BY, et al. (2018). Effect of evening primrose oil on Korean patients with mild atopic dermatitis: A randomized, double-blinded, placebo-controlled clinical study.DOI:

- Dhar D, et al. (2017). A comparative study of centchroman vs danazol vs evening primrose oil in the management of mastalgia and fibroadenoma.

- Evening primrose oil. (2016).

- Majdinasab N, et al. (2018). The effect of evening primrose oil on fatigue and quality of life in patients with multiple sclerosis.DOI:

- Munir R, et al. (2017). An updated review on pharmacological activities and phytochemical constituents of evening primrose (genus Oenothera).DOI:

- Osman M, et al. (2016). Evening primrose oil reducing serum lithium concentration. DOI:

- Arora T, et al. (2018). Microbial fermentation of flaxseed fibers modulates the transcriptome of GPR41-expressing enteroendocrine cells and protects mice against diet-induced obesity. DOI:

- Bommareddy A, et al. (2009). Chemopreventive effects of dietary flaxseed on colon tumor development. DOI:

- Cooley J. (2018). Should you be concerned about flaxseed?

- Flaxseed and flaxseed oil. (2016).

- Khalesi S, et al. (2015). Flaxseed consumption may reduce blood pressure: A systematic review and meta-analysis of controlled trials. DOI:

- Wiltgen A, et al. (2017). Determination of flaxseed and its health promoting compounds role in nuclear factor-kB and its inhibitor gene expression.

- Singh BR, et al. (2016). Comparative antimicrobial activity of tea tree oil (Melaleuca oil) and common topical antimicrobials against bacteria associated with wound and topical infections.DOI:

- Tea tree oil.(2016).

- Tea tree oil: Remedy and poison. (n.d.).

- Echinacea. (2016).

- Echinacea. (2018).

- Hostettman K. (2003). History of a plant: The example of Echinacea.

- Karsch-Völk M, et al. (2015). Echinacea for preventing and treating the common cold.

- Linde K, et al. (2006). Echinacea for preventing and treating the common cold.

- Park S, et al. (2018). Echinacea purpurea protects against restraint stress-induced immunosuppression in BALB/c Mice. DOI:

- Percival SS. (2000). Use of echinacea in medicine. DOI:

- Grape seed.(2018).

- Grape seed extract.(2017).

- Grape seed extract. (n.d.)

- Kaur M, et al. (2009). Anticancer and cancer chemopreventive potential of grape seed extract and other grape-based products. DOI:

- Cardia GFE, et al. (2018). Effect of lavender (Lavandula angustifolia) essential oil on acute inflammatory response. DOI:

- Lavender. (2016).

- Lehrner J, et al. (2005). Ambient odors of orange and lavender reduce anxiety and improve mood in a dental office. DOI:

- Moss M, et al. (2009). Aromas of rosemary and lavender essential oils differentially affect cognition and mood in healthy adults. DOI:

- Oana. (2018). Famous agricultural areas in the world – Provence, France.

- Summary of lavender. (2018).

- Al-Dabbagh B, et al. (2019). Antioxidant and anticancer activities of chamomile (Matricaria recutita L.). DOI:

- Amsterdam JD, et al. (2009). A randomized, double-blind, placebo-controlled trial of oral Matricaria recutita (chamomile) extract therapy of generalized anxiety disorder.

- Chamomile. (2016).

- Combs D. (2016). German chamomile vs. Roman chamomile: What’s the difference?

- Mao JJ, et al. (2016). Long-term chamomile (Matricaria chamomilla L.) treatment for generalized anxiety disorder: A randomized clinical trial. DOI:

- Srivastava JK, et al. (2010). Chamomile: A herbal medicine of the past with bright future.

- Subiza J, et al. (1990). Allergic conjunctivitis to chamomile tea.

Share this article



Medically reviewed by Debra Rose Wilson, Ph.D., MSN, R.N., IBCLC, AHN-BC, CHT — Written by Shelby Deering —  Updated on February 28, 2019

### Read this next



Written by Melissa Groves

© 2024 Healthline Media LLC. All rights reserved. Healthline Media is an RVO Health Company. Our website services, content, and products are for informational purposes only. Healthline Media does not provide medical advice, diagnosis, or treatment. See additional information.

OUR BRANDS