9 Best Herbal Teas for Digestion
Whether for taste, ritual, or remedy (or often a little of each), people worldwide have been consuming tea for thousands of years!
(Side note: tea has a VERY special place in my heart! My entire nutrition career began with a cup of green tea at the Winchester Hospital coffee shop back in 2004.)
Tea as a digestive ally
One thing I can say with great confidence after a decade of ongoing research, some personal health challenges (#woundedhealer), and clinical experience is there are a multitude of teas which make wonderful natural, complementary alternative “herbal allies” in supporting our digestive health (among many, many other things!).
From calming a nervous stomach to nourishing/soothing a damaged gut lining and more… there’s a lot to be said about the power of tea for digestion!
Tea is also a wonderful plant-based alternative to bone broth, collagen, or gelatin as a “functional food” for people following a vegan or vegetarian lifestyle looking to support their digestion naturally.
Although there are many dozens of teas and herbs that help various types of gut-related ailments (which I could ramble on about for weeks on end), I’m going to share with you my top 9 favorites (and why!).
First, a few quick notes and disclaimers:
The information and recipes I share in this article are meant for educational purposes. This content is not meant to replace medical advice. Everyone has individualized needs, so make sure to consult your doctor, dietitian, and/or if you’ve got any kind of medical condition, are pregnant/nursing or are taking medication!
I use traditional methods of herbal tea preparation including infusions and decoctions with organic fresh or dried loose herbs, which are often less chemically treated/processed and more potent compared to commercial tea bag alternatives. Commercial tea is lovely for enjoyment and ritual, but it doesn’t always offer the same degree of health benefits compared to traditional preparations based on many clinical studies. (Not always the case, but if you’ve tried commercially prepared teas for digestion in the past and they *didn’t work*, that might be one reason!)
That said, I’ve included some optional but recommended sources and links where you can purchase organic loose dried herbs online!
Please note I’m a proud affiliate for Starwest Botanicals and Mountain Rose Herbs. These online apothecaries offer sustainably-grown, ethically harvested, organic loose herbs and practice in alignment with my values.
- If you make a purchase using any of my affiliate links, I make a small commission at no extra cost to you. I turn down ~99% of affiliate opportunities and only work with companies I trust and use myself. Thank you for your support!
1. Ginger (fresh root infusion)
Latin botanical name: Zingiber officinale
This popular warming, pungent, “zingy” (pun intended) rhizome has been used by people in Southeast Asia for over 5,000 years! Ginger is still used by many people worldwide as both a digestive aid and culinary ally… for good reason!
Ginger tea for digestion
Ginger tea has been reported to provide significant relief for people experiencing nausea whether from motion sickness, digestive havoc, or side effects related to chemotherapy/HIV retroviral treatment (1).
Due to its carminative, moving and dispersive nature, ginger is also often used as a catalyst in conjunction with other herbs and protocols to help support people struggling with symptoms of “stagnant digestion” such as bloating, gas, constipation, and/or “dysbiosis” (imbalance of the “good” and “bad” bacteria in the gut) (2).
For the record, there are lots of other wonderful documented benefits of ginger outside of digestive health too! I just don’t have that many hours in a day to talk about alllll the things. 😉
Fresh versus dried ginger
Although dried ginger is found in studies to have a higher antioxidant activity (3), I’ve found anecdotally that fresh ginger is better tolerated and more effective from a digestive standpoint compared to dried ginger, which can actually be too hot and too potent for many people from a constitutional standpoint.
Ginger contraindications/safety concerns
- Ginger thins the blood, so consult a doctor before adding ginger into your routine if you’re on any kind of blood thinning medication!
- Based on clinical experience, ginger tea is “hit or miss” when it comes to heartburn, and I’d advise you to stay clear of ginger in cases of ulcers of any kind due to the “hot” constitutional nature of both ginger and this particular medical condition.
- Proceed with caution and consult a doctor before taking ginger if you’re pregnant or nursing.
How to brew a fresh ginger tea infusion
- Peel and slice/shred a 1-inch piece of fresh ginger root. (The smaller you slice it, the more potent your infusion will be.)
- Steep in 8 to 16 oz. of just-boiled water for 5 to 15 minutes. Add some fresh lemon and raw honey for extra flavor!
- Recommended use: Enjoy before or immediate after meals a few times a day.
Latin botanical names: Matricaria recutita (German Chamomile) and Chamaemelum nobile (Roman Chamomile)
Chamomile tea is a classic, time-tested herbal remedy for gut health! The two variations of chamomile used by people for supporting digestion and mental health are German chamomile and Roman chamomile.
As a well-known “nervine” (herb shown to soothe an overactive nervous system), chamomile is also often used as a sleep aid and helps take the edge off after a stressful day. In spite of its “nervine” properties, chamomile is a wonderful way to help calm a nervous stomach!
In addition to being a nervine, chamomile also has a tendency towards bitter taste/energetic properties which may explain why it supports digestion in so many ways. Chamomile tea has been shown in many cases to help reduce gastrointestinal discomfort significantly for people with symptoms varying from gas, bloating or stomach upset, to ulcers, gastrointestinal disorders, and even hemorrhoids (4).
In my clinical practice I’ve also seen people benefit from chamomile tea for heartburn anecdotally, even when just using a mainstream commercial chamomile tea preparation – although I still prefer the traditional method from a clinical AND taste standpoint. (There’s nothing like a traditionally prepared relaxing cup of dried chamomile flower petal infusion to wind down the day – especially with a little honey!)
Chamomile for children
Another thing I love about chamomile is how incredibly safe and gentle it is. For example, people even use chamomile (in very, very small amounts) to calm colic for babies at least four to twelve months of age (5) and it’s generally safe for children of all ages. (I recommend consulting a neonatal/pediatric clinical herbalist and doctor for customized recommendations and medical clearance before administering chamomile to a baby, of course!)
Chamomile contraindications/safety concerns
- Sedative interaction: Chamomile is mildly sedative so it may amplify the effects of a sleep aid or sedative mediation. Consult a doctor before taking chamomile if you take these kinds of medications.
- Allergic reactions: Chamomile is part of the ragweed family so it can occasionally cause an allergic reaction in people allergic to ragweed.
- Chamomile tea for infants: Safety guidelines and dosing recommendations for infants will vary greatly depending on many different factors and contexts. I don’t specialize in infant/neonatal nutrition or herbal medicine so I don’t feel comfortable providing any kind of guidelines around chamomile tea for infants. That said, make sure to consult your doctor and any other neonatal clinical for custom guidelines before administering herbal tea of any kind to your baby!
- Honey and infants: although honey goes great with tea, make sure to never give any kind of honey to infants under two years old due to the risk of botulism.
How to brew a traditional chamomile flower petal infusion
- Steep 1 teaspoon to 1 tablespoon of dried chamomile flower petals in 8 to 16 oz. of very hot water for 10 to 20 minutes. The longer you steep your chamomile infusion, the stronger the potency and the more bitter the taste!
- You can enjoy chamomile tea hot or iced, depending on your preference. It lasts for up to 3 days in the fridge in a sealed mason jar.
Latin botanical name: Mentha x piperita
Peppermint is another wonderful time-tested herb valued and used around the world for thousands of years for multiple reasons. Digestive health and breath-freshening are among the most well-known uses of peppermint! The fresh, clean, naturally minty flavor and uplifting, cooling experience of peppermint leaves are added bonuses if you ask me. 😊
Peppermint and the gut
Clinical studies have confirmed the powerful, positive impact peppermint extracts can have for people suffering from IBS (6).
Although there aren’t specific studies on peppermint tea and IBS, tea does contain the same aromatic constituents as peppermint oil (menthol and menthone) so it’s likely the benefits extend beyond peppermint oil (6)! Peppermint tea, for example, has been anecdotally reported by many to relieve stomach discomfort as well as mild symptoms of gas and bloating – especially when taken before or after meals a few times a day.
Peppermint leaf constituents are shown to reduce lower gastrointestinal muscle spasms which can relax an over-active gut, similar to the mechanism of chamomile tea!
Peppermint contraindications/safety concerns
Similar to ginger, peppermint is hit-or-miss for people with heartburn since it seems to reduce esophageal spasms by relaxing the esophageal sphincter (flap which connects the stomach to the esophagus). This can be for better or worse, depending on the underlying root cause of the symptoms!
You should avoid peppermint or proceed with caution and consult a doctor /other specialized clinician before taking peppermint if you have heartburn, reflux, esophagitis, hiatal hernia, or kidney stones (7).
How to brew a peppermint leaf tea infusion
- Steep 1 teaspoon to 1 tablespoon of fresh or dried peppermint leaves in 8 to 16 oz. very hot or just-boiled water for 5 to 15 minutes. The more tea you use and the longer you steep it, the more potent your herbal tea infusion will be!
- Recommended use: Drink 5 to 20 minutes before a meal, or immediately after a meal, a few times a day as needed.
Latin botanical name: Foeniculum vulgare
Fennel is one of those hidden treasures we can often find sitting in the fresh produce aisle and/or spice section at the local supermarket.
Just because fennel is low-cost and available to us in abundance, that doesn’t undermine its incredible power in supporting digestive health for people of all ages!
Fennel uses and benefits
Due to its sweet taste (similar to licorice), fennel is used worldwide for culinary purposes.
Fennel is also now a popular home remedy for digestive health, especially among people who embody the practice of Ayurveda (a form of evidence-based lifestyle medicine which originated in India thousands of years ago).
In Ayurvedic herbal medicine it’s encouraged for people to chew on fennel seeds in combination with other herbs after a meal to discourage symptoms of gas/bloating.
Fennel is a safe, kid-friendly “carminative” (stimulates digestion, expels gas) which is often used in conjunction with catnip for kids AND adults with tummy turbulence (8).
Fennel is also found to have anti-microbial, anti-fungal properties (9) which can be supportive for people suffering from dysbiosis!
Fennel contraindications/safety concerns
- Large amounts of fennel over time have been shown in some cases to demonstrate a mild estrogen-like effect in the body (10). Fennel interacts with some medications including birth control pills, certain antibiotics, and medications which alter the blood (clotting, blood pressure) in any way.
- Consult a doctor before using fennel if you’re on medication, have a hormone-sensitive cancer, or are pregnant/breastfeeding!
How to brew a fennel tea infusion
- Steep 1 teaspoon to 1 tablespoon of fennel seeds in 8 to 16 oz. very hot or just-boiled water for at least 15 to 20 minutes. Fennel seeds can also make a great synergist to be added to other digestive tea blends as well!
- Enjoy immediately after a meal for optimal benefits a few times a day or as needed.
How to make a fennel tea decoction
- Simmer 1 tablespoon of fennel seeds in ~3 to 4 cups (24 to 32 oz.) of water or milk/milk substitute for about 10 to 20 minutes. This flavor and potency of a fennel decoction will be significantly stronger compared to the infusion!
- Enjoy 1 cup (8 oz.) at a time, up to 3-4x/day max, as needed.
Latin botanical name: Calendula officinalis
“As within, so without.” – Ancient Hermetic principle of alchemy
One thing I love about herbal medicine is the plant wisdom it contains.
For example, lots of herbs that are well-known to support our skin (the outmost barrier which separates the body’s internal organs from the outside world) also seem to have a similar parallel benefit to the gut lining, which is basically our internal “skin” on some level in that it also serves as a boundary between our internal organs and the outside world.
(Fun fact – the gut lining is technically not INSIDE the body… it’s more like the donut hole which is not part of the donut!)
Lead into calendula.
Although you may or may not be familiar with calendula, this skin-soothing, gut-supportive tonic herb is also often referred to as “pot marigold” (which is different than the annual garden version of marigold flowers that most of us know and love)!
Calendula flower petal preparations are often used topically to help speed tissue healing after injuries, and are also commonly used by many Western herbalists to support people internally in efforts to reduce gut inflammation (8, 10).
Calendula’s actions and energetic properties relevant to the gut lining
Calendula is well known for being astringent, toning and tightening in action. This can be ideal for supporting some people with leaky gut (in conjunction with other medical/nutrition/herbal protocols) in that the “tight junctions” between the cells of the digestive tract can stand to tighten up!
Calendula tea and digestion
Tea infusions in my opinion are one of the most clinically optimal ways to administer calendula (as opposed to tinctures or capsules), since it’s a very nutrient-dense herb and tea is a great way to coat the gut lining!
However, there’s a downside…
Calendula tea is very, very bitter in taste! I can’t even count on one hand the amount of times I’ve successfully finished an entire cup of straight calendula tea. 😀
That said, calendula is more enjoyable (or palatable) when used in combination with other herbs (stay tuned for my gut healing tea recipe coming soon!) or when sweetened with a little bit of raw honey.
Calendula contraindications/safety concerns
- Generally speaking, calendula tea is very safe, even for children (consult a clinical pediatric herbalist for dosing recommendations which will be lower compared to adults).
- There are no herb-drug interactions with calendula when taken as tea, but it can potentially interact with some medications when taken in other forms.
- Calendula of any kind is not safe for women trying to conceive, or during pregnancy/breast-feeding.
- Calendula can sometimes result in allergic reactions for people who have a daisy family or ragweed allergy.
How to brew a calendula flower petal tea infusion
- Steep 2 teaspoons of dried calendula flowers or flower petals in hot (but not boiling) water for no more than 10 to 15 minutes. Add a teaspoon or two of raw honey to sweeten. Can combine with other herbs for better taste and more synergistic gut health outcomes.
- My two cents: I recommend drinking 4 to 8 oz. (1/2 cup to 1 cup) of calendula tea infusion 15 to 20 minutes before or a few hours in between meals if possible! The petals are less bitter than the whole flowers.
Latin botanical name: Althea officinalis
First and foremost, I should mention… this kind of marshmallow root is definitely NOT the same kind of “marshmallow” as the sweet fluffy stuff we use in America for making S’mores… or the Easter Peeps that so many like to microwave, for that matter! Although I personally find Althea officinalis to be so much more awesome than marshmallow candy. (Maybe I’m biased?)
Marshmallow root uses
Marshmallow root, like calendula, has been incorporated in folk remedies for hundreds if not thousands of years! Marshmallow root is also used in herbal formulas/preparations for skin conditions AND digestive woes (“as within, so without!).
Marshmallow vs. calendula for the gut: What’s the difference?
Although both marshmallow root and calendula are very nutritious herbs when extracted in water, and they both seem to benefit the skin and the gut, the main difference between the two is their “herbal energetic” properties and constitutional actions on the body.
- While calendula is more drying, bitter, astringent and toning/tightening, marshmallow root is sweet, lubricating and “mucilaginous” (gets slimy when in contact with water), which makes marshmallow root nourishing and supportive to the mucous membranes of the gut and throughout the body. (8, 10)
Two totally different personalities if you ask me!
Nonetheless, depending on what your body needs, both marshmallow and calendula can benefit those looking for natural gut health support.
Marshmallow root’s slippery, slimy constitutional actions (super appetizing, I know) help to temporarily coat and soothe the mucous membranes of the gut lining which is helpful for people with raw, damaged tissue that needs some extra support.
Marshmallow root safety considerations
One last thing I love about marshmallow root tea is that it’s very, very safe for people of all ages (toddlers and up) as long as it’s not over-consumed (3 to 4 cups a day max for adults). Consult a pediatrician and pediatric clinical herbalist before giving marshmallow root (or any herbs) to your kiddo’s, of course.
How to make marshmallow root decoction
- Bring 4 cups of water + 1 to 2 tablespoons of chopped (not powdered) marshmallow root to a simmer over low-medium heat.
- Simmer for at least 20 minutes or up to an hour (but don’t let too much water evaporate!).
- Strain and enjoy 10-20 minutes before meals or a few hours in between meals.
- Can save via refrigeration for up to 3 days.
How to make a marshmallow root cold brew infusion
- Leave in the fridge overnight a 1-quart mason jar of ~3 cups of filtered water and 1 tablespoon of loose chopped OR powdered marshmallow root.
- Strain the next morning and sip before/between meals.
- Good for up to 3 days in the fridge.
Bonus idea: Use your marshmallow root decoction/cold brew infusion as an alternative to water to cook your oatmeal, rice or other staples that use water! (From a palatability standpoint: this may or may not bode well with the other tea’s…)
A few last notes on marshmallow
- Marshmallow root is also great in capsule form as this helps it to travel far down the LOWER gastrointestinal tract, if needed there… but that’s a conversation for another time – and something we’ll be covering in depth in my upcoming Leaky Gut Fundamentals course! 😉
- Although marshmallow root has very similar actions in the body to the more mainstream “slippery elm” bark, I’ve chosen NOT to endorse slippery elm on my list of herbal teas for digestion because that plant has been over-harvested for many years, and is sadly now on the endangered plant list at risk of extinction in the wild. Why would we select slippery elm as our herb of choice when we have SO many other wonderful gut health-promoting herbal options available to us in abundance? (Keep reading!)
7. Licorice root (as a synergist in other tea blends)
Latin botanical name: Glycyrrhiza glabra
First things first: Just like herbal marshmallow is totally different from the marshmallow candies we all know and love, herbal licorice root is also pretty far removed from its candy counterpart! (Although in many cases, candy companies do use real herbal licorice root to flavor licorice candy – it’s just extremely diluted.)
Herbal licorice root is very popular and often used in small amounts as part of herbal formulas by many Traditional Chinese Medicine (TCM) practitioners as well as western herbalists.
Licorice root is very sweet (exponentially sweeter than sugar!) and mucilaginous like marshmallow, which makes it a wonderful candidate for supporting gut health as well as ulcers, heartburn, reflux and even constipation (10, 11).
(There are many other actions and uses for licorice root, but I’m only focusing on gut health for the purposes of this post!)
But when it comes to licorice, a little bit goes a long way – and it’s not safe for everyone!
Licorice root contraindications/safety concerns
- Licorice contains small amounts phyto-estrogens, so proceed with caution and consult an expert before adding licorice root to your gut health routine if you’ve got any kind of hormonal imbalance.
- Licorice root can increase blood pressure, reduce potassium, and promote fluid retention when consumed in excess.
- Avoid licorice root if you’re struggling with/in recovery from bulimia, or if you’ve got any kind of heart condition, or if you’re on medication of any kind.
- Avoid licorice root if your body is low in potassium or if you’re taking diuretic medications (“water pills”).
- A safer alternative to licorice root tea (if deemed appropriate by your doctor or other qualified clinician) can be “deglycyrhizinated licorice” (DGL) in that it doesn’t raise blood pressure or deplete potassium. But still don’t take this without medical supervision!
Licorice root tea for digestion?
Instead of giving you a recipe for straight licorice root tea (since that would be VERY sweet and VERY intense)… licorice is much better when used in small amounts as an addition to other herbal formulas! If licorice is a safe and effective “herbal ally” for you, I recommend adding just a small amount (1/2 a teaspoon or less) to another herbal tea blend of your choice (it can any of the other options mentioned in this article, provided you meet the safety criteria and it’s in alignment with your treatment plan!).
Botanical latin name: Plantago major
Although these plant names are very similar to a lot of popular foods, it seems I’ve got lots of clarifying to do in this article!
As an FYI: when I mention “plantain”, I’m NOT talking about the same plant as the delicious tropical fruit which looks a lot like bananas. But I do love those too (fried plantains… YUM!). 😉
Plantago major, or “plantain weed”, is actually a common weed which grows in abundance all over the world. I’ve seen it in the springtime all over the place here in central Texas, and I’ve also noticed it while visiting my homeland in Massachusetts over the summertime these last few years!
Although it’s wonderful to harvest your own plantain leaves, I don’t cover plant identification here and so if you’re interested in fast-tracking your way to plantain leaf tea I encourage you to purchase your own organic dried plantain leaves from Starwest Botanicals, Mountain Rose Herbs, or Frontier.
If you’ve read this entire article up to this point, you’ll notice there’s a lot of overlap among herbs that have similar health uses/benefits:
- Like marshmallow and licorice root, plantain leaves are nourishing and mucilaginous. This makes plantain leaves nourishing and soothing to an inflamed gut!
- Like calendula and marshmallow root, plantain leaves are used by herbalists both topically (for skin) and internally (for gut health!) (8, 10).
I personally don’t mind the taste of plantain leaf tea infusions – plantain tea reminds me a lot of green tea – but it’s not for everyone. In that case, you can blend it with other herbs or stick to something you know you’ll enjoy!
Plantain contraindications/safety concerns
- Plantain leaves can be high in FODMAPS, so stick to tea and don’t consume this in a salad if you’re on a low-FODMAP diet or worried about yeast!
How to make a plantain leaf tea infusion
- Steep 1 tablespoon of dried plantain leaves in ~12 ounces of very hot/just-boiled water for about 15 to 20 minutes. Add some raw honey to taste, if it doesn’t bother you (honey is also high FODMAP).
- Enjoy between meals anywhere from 1x/day to a few times a day (adults)!
Latin botanical name: Viola tricolor
Although violet is the last on my list of herbal teas for digestion, it certain is not the least of my favorites!
Growing up in Massachusetts, every spring/summer my backyard was covered with these beautiful, delicate purple flowers (among other herbs like dandelions and chickweed, to name a few). Little did I know I was surrounded by so much wonderful plant medicine!
Violet and the gut
Violet leaves are also demulcent (mucilaginous), as well as cooling and soothing to an inflamed gut (8). Just like calendula, marshmallow, licorice and plantain, these qualities make violet leaf based herbal preparations an ideal candidate for supporting the lining of the gut!
Both the leaves and flowers of Viola tricolor can be enjoyed raw in salads, dried in tea, or tinctured.
My personal preference is some seasonal iced violet tea (lightly sweetened) in the spring and summer months – see below!
Violet contraindications/safety concerns
This plant is incredibly nutritious and very safe with no known contraindications aside from potential allergic reactions for people with certain types of pollen allergies (12).
How to create and enjoy a delicious, nutritious violet tea infusion
- Steep 1 tablespoon of dried violet herb in ~12 to 16 oz. very hot water for at least 15-20 minutes. The longer you steep your tea, the more nutrients you’ll extract into the water! (This may impact the taste.)
- Enjoy 2 to 3 (8 oz.) cups daily hot or iced, as desired/as needed.
- Optional: sweeten with raw honey to taste!
- Store in sealed mason jars in the fridge for up to 3 days.
That is all for now!
Thanks SO much for being here and taking the time to read about my favorite teas for digestive health. I hope this article brings you more clarity and understanding around the power and roles that nature can play on your health journey. I know we covered LOTS of information here but remember this is not customized medical advice! Everyone is different. (Humans are like snowflakes…)
That said, make sure to consult qualified clinicians for custom recommendations.
If you’d like more where all of this came from, I also invite you to join the waiting list and I’ll keep you posted on my upcoming Leaky Gut Fundamentals online program!
Lots of love,
- De la Foret, Rosalee. Alchemy of Herbs. 1st ed., Carlsbad, California, Hay House, Inc., 2017.
- Langner, Elke, Stefan Greifenberg, and Joeg Gruenwald. “Ginger: history and use.” Advances in therapy1 (1998): 25-44.
- Yuxin Li, et al. Chemical characterization and antioxidant activities comparison in fresh, dried, stir-frying and carbonized ginger. Journal of Chromatography B. 1011 (2016): 223-232.
- Srivastava, Janmejai K et al. “Chamomile: A herbal medicine of the past with bright future.” Molecular medicine reports 3,6 (2010): 895-901.
- Weizman, Z et al. “Efficacy of herbal tea preparation in infantile colic.” The Journal of pediatrics vol. 122,4 (1993): 650-2.
- Khanna, Reena et al. “Peppermint oil for the treatment of irritable bowel syndrome: a systematic review and meta-analysis.” Journal of clinical gastroenterology vol. 48,6 (2014): 505-12.
- McKay, Diane L, and Jeffrey B Blumberg. “A review of the bioactivity and potential health benefits of peppermint tea (Mentha piperita L.).” Phytotherapy research : PTR vol. 20,8 (2006): 619-33. doi:10.1002/ptr.1936
- Noel Groves, Maria. Body Into Balance: An Herbal Guide to Holistic Self Care. 1st, North Adams, Massachusetts, Storey Publishing, 2016.
- Rather AA, et al. “Foeniculum vulgare: A comprehensive review of its traditional use, phytochemistry, pharmacology, and safety”. Arabian Journal of Chemistry 9, 2 (2016): S1574-S1583.
- Horne, Steven, and Thomas Easley. The Modern Herbal Dispensatory: A Medicine-Making Guide. Berkeley, California, North Atlantic Books, 2016.
- Fiore, Cristina et al. “A history of the therapeutic use of liquorice in Europe.” Journal of ethnopharmacology vol. 99,3 (2005): 317-24.
- Committee on Herbal Medicinal Products (HMPC). “Assessment Report on Viola Tricolor L. and/or Subspecies Viola Arvensis Murray (Gaud) and Viola Vulgaris Koch (Oborny), Herba Cum Flore.” European Medicines Agency, European Medicines Agency – Science Medicines Health, 25 Nov. 2010, ema.europa.eu/en/documents/herbal-report/final-assessment-report-viola-tricolor-l/subspecies-viola-arvensis-murray-gaud-viola-vulgaris-koch-oborny-herba-cum-flore_en.pdf.