Nasturtiums are both edible and medicinal and can easily be grown in the garden. The flowers, leaves and seeds, which all have a hot and pungent taste, can all be consumed fresh in salads and in other culinary dishes. Its spicy taste is due to the presence of compounds known as mustard seed oils. The mustard seed oils in nasturtium have been proven to be effective against many bacterias, viruses and fungal infections. The leaves and flowers of nasturtiums are rich in antioxidants and other vital nutrients, including vitamin C, potassium, phosphorus, magnesium, calcium, manganese, copper, zinc and iron. They also contain aromatic oils and carotenoids which have antioxidant effects (1).

Nasturtium is most well known as a urinary antiseptic, which may be useful for a threatening urinary tract infection (UTI) — this is most often taken as an infusion (tea). It combines well with herbs like hibiscus, cornsilk and plantain for UTIs and works by reducing inflammation whilst also addressing the bacterial imbalance (1,2). It also increases diuresis (3). These are all important actions for herbs used to approach the treatment of UTIs. 

In modern herbalism, nasturtium is considered to be an important herb for the treatment of cystitis and as part of a healing strategy for recurrent UTIs (2,3). However, it is important to note that whilst it may be able to assist in acute infections, serious or recurrent UTIs are most effectively treated under the care of a medical herbalist. Oftentimes these types of presentations require a course of treatment under the care of a herbalist to help address the root cause. 

Nasturtiums can be eaten or drunk as an infusion to help reduce the symptoms of colds and flus, particularly where there is catarrh in the upper respiratory tract, cough and bronchitis (4).

In Germany, a herbal antibiotic made with nasturtium and horseradish root is used to treat acute sinusitis, acute bronchitis und acute UTIs. Its anti-infective effects are due to the presence of volatile oils in nasturtium, such as myristicin, α-terpinolene and limonene (1).

Due to nasturtium’s spicy and pungent nature, it has a warming and stimulating effect on the cardiovascular system which helps to improve the function of the peripheral microcirculation. Consequently, it can also help to reduce mild muscular pains, menstrual pain, hair loss and assist in the healing of infected and slow-healing wounds (4).

Nasturtium is a hot and pungent relaxing vasotonic alterative. It has what may be seen as opposing or contradictory effects on the vascular system — as it both tones and relaxes the capillaries. 

These effects on the cardiovascular system are in fact symbiotic and they can offer valuable physiological support for those who hold tension or constriction with a simultaneous weakness of the vascular tissues. Nasturtium allows for improved integrity of the vasculature systemically, whilst relaxing the vascular tissue (3).

As a warming, pungent medicine, nasturtium exerts great influence on the cardiovascular system by innovating the cells through improved blood movement — this effect reaches every organ system through its primary influence upon the circulation. Due to this deeply nourishing and warming effect, nasturtium helps to improve an overall sense of vitality and radiance in the body and mind (5).

Nasturtium was brought to Europe from South America in the 16th century. By the 18th century, the use of nasturtium as medicine became more common throughout Europe. Their high vitamin C content meant they were sometimes used in the treat scurvy, a condition caused by vitamin C deficiency which was common among sailors (6).

Cardiovascular system

Nasturtium has a significant impact on the cardiovascular system through its ability to both relax and tone the vasculature (3). Its vasodilatory effects may be relevant for the treatment of coronary heart disease alongside other herbs that can help support the cardiovascular system on both an anatomical and physiological level (2).

It has been shown to exhibit pronounced diuretic and antihypertensive activities, along with a number of other positive effects on the cardiovascular system, through its anti-sclerotic and antioxidant actions (2,7).

Studies have explored the effects of nasturtiums in diabetic patients for its cardioprotective potential. A randomised crossover trial, involving a 10-patient study, found a reduction of blood lipid profile and low definition lipoproteins, risk factors associated with cardiovascular disease (8).

Whilst modern herbalists may not use nasturtiums as frequently as they may have once had, there is mounting evidence for its positive potential for improving cardiovascular health.

Respiratory system

Nasturtium is indicated in cold, damp and phlegmatic conditions of the respiratory system, often characterised by excess mucus production, such as cough, sinusitis, chronic bronchitis and chronic asthma (2). It helps to address excess phlegm and stagnation by encouraging expectoration from the lungs.

Nasturtium is used to treat bacterial infections in the respiratory system due to its antimicrobial activities (1,4). One of the compounds thought to be important for these bacteriostatic effects is called benzyl isothiocyanate, which is eliminated via respiration. This means it passes directly through the air sacs in the lungs (9).

The strong volatile components in nasturtium also acteffectively as a respiratory decongestant. The pungent compounds in nasturtium called glucosinolates contain portions of sulphur, which exhibit some antibacterial activity. These effects can be valuable in fighting chronic respiratory infections characterised by mucous congestion (3,10).

Studies have explored the effects of glucosinolates and their by-products on SARS COVID-19 virus. The findings suggest that their potent anti-inflammatory and antioxidant effects reduce levels of inflammatory cytokines (proteins that moderate immune response via cell signalling that initiates cell activation, differentiation and proliferation). Sometimes the body produces a severe immune reaction during a viral infection, in which the body releases an excess of these cytokines into the blood too quickly — a reaction which has been observed in covid patients. The effects of glucosinolates may be useful in helping to reduce the risk of what is known as a cytokine storm (10).

Urinary system

One of nasturtium’s most common uses is as a natural urinary antiseptic, diuretic and anti-inflammatory medicine. It is used to address bacterial infections in the urinary system (2). The antibacterial compound benzyl isothiocyanate in nasturtium is eliminated via the urinary system which explains why this herb has a strong reputation for use in urinary tract infections (9). This application also extends, in its traditional use, to kidney stones (2).

Skin and hair

The juice of nasturtium has been traditionally used to treat lipomas, polyps and other skin conditions. Internal use of the tincture may also be useful for alopecia and baldness whilst other references suggest using an infusion (topically) to help stimulate hair growth and relieve dandruff (2). Many herbalists may recommend using a topical and internal approach to treatment.

Musculoskeletal system

Mustard oil glycosides are present in nasturtiums, as well as herbs like horseradish, cabbage and black mustard. These compounds are a primary irritant which is why repeated contact with plant material on the skin can have abrasive effects. However, this action is sometimes exploited for the benefit of localised joint inflammations through topical application of a poultice or ligament. This rubefacient action promotes localised increased blood flow, which can help draw the natural healing qualities in the body to the affected area (11).

Internal use of nasturtiums also may be helpful in reducing inflammation and poor blood movement that can contribute to muscular pains, these effects occur due to nasturtium’s ability to improve peripheral micro-circulation thus increasing blood supply to the muscles (4). 

There are currently very few quality human clinical trials on nasturtiums. However, studies have been carried out to analyse its pharmacological actions. Through in vitro research, nasturtiums have been shown to have potent antibacterial activities. The studies demonstrated antibacterial and anti-fungal properties of nasturtium juice which were determined by the Wells method. The juice of nasturtium was highly active against Staphylococcus aureus, Candida albicans, Pseudomonas aeruginosa and Escherichia coli (2).

A pilot study: Effects of nasturtium on insulin resistance and lipid profile in pre-diabetic patients

A randomised crossover pilot study was carried out to explore the effects of nasturtium on patients with insulin resistance using freeze-dried nasturtium drink. Ten patients were assigned to either receive a nasturtium drink or a placebo for a period of four weeks. After this time, the treatments were crossed for another four weeks. Biomarkers related to insulin resistance and lipid profile were measured at the beginning and the end of the treatment. The results showed a significant decrease in the concentration of low density lipoprotein (LDL) as well as oxidised LDL in the treatment group. The study concludes that nasturtium may affect biomarkers related to cardiovascular disease that are abnormal in patients with type II diabetes (8).

Nasturtium (Indian cress, Tropaeolum majus nanum) dually blocks the COX and LOX pathway in primary human immune cells. 

An in vitro study was carried out to investigate the potential of aqueous extract of nasturtium to inhibit inflammatory responses in primary human cells. Human peripheral blood mononuclear cells (PBMC) were either treated with plant extracts or chemical fractions. The study identified that nasturtium caused a strong concentration dependent suppression of a specific inflammatory signalling pathway suggesting that the mechanism of action is unique to this plant and also different to non-steroidal anti-inflammatory drugs (NSAIDs). This study provides some insight into the mechanism for nastrurtium’s anti-inflammatory effects. Further clinical research is required to fully explore the potential of this herb in the management of inflammation (12).

The compounds in nasturtium that are responsible for its pungent properties are called glucosinolates. They are also found in horseradish and mustard. These compounds in themselves are not pungent, but when they come into contact with the enzyme myrosinoase located within the plant cells, the aglycone is formed which then rearranges into the pungent chemicals that are so characteristic of these plants.

Glucosinolates have been well researched through in vitro, in vivo and human studies for their anti-carcinogenic properties. They are also found in high levels in brassica vegetables (13).

Nasturtium is a cultigen which is believed to have derived from South America. It is an annual which grows primarily in the subtropical biome. It is thought to have derived from T. ferreyrae × T. minus (17).

There is currently no data on the sustainability status of nasturtium, as no assessments have been made by NatureServer, IUCN or CITES (18,19,20). 

Habitat loss and over-harvesting from the wild are two of the biggest threats faced by medicinal plant species. There are an increasing number of well-known herbal medicines at risk of extinction. We must, therefore, ensure that we source our medicines with sustainability in mind.

The herb supplement industry is growing at a rapid rate and until recent years a vast majority of medicinal plant produce in global trade was of unknown origin. There are some very real and urgent issues surrounding sustainability in the herb industry. These include environmental factors that affect the medicinal viability of herbs, the safety of the habitats that they are taken from, as well as the welfare of workers in the trade.

The botanical supply chain efforts for improved visibility (transparency and traceability) into verifiably sustainable production sites around the world is now certificated through the emergence of credible international voluntary sustainability standards (VSS). 

Read our article on Herbal quality and safety: What to know before you buy and Sustainable sourcing of herbs to learn more about what to look for and questions to ask suppliers about sustainability.

Herbal medicines are often very safe to take, however, it is important to buy herbal medicines from a reputed supplier. Sometimes herbs bought from disreputable sources are contaminated, adulterated or substituted with incorrect plant matter.

Some important markers for quality to look for would be to look for certified organic labelling, ensuring that the correct scientific/botanical name is used and that suppliers can provide information about the source of ingredients used in the product.

A supplier should be able to tell you where the herbs have come from. There is more space for contamination and adulteration when the supply chain is unknown.

Nasturtiums will grow in most locations in well-drained soil with full sun. They will grow in partial shade but will not bloom as well without the full sun. 

The seeds can be sown directly in the garden in late spring to early summer once all danger of frost has passed or they can be started indoors in seed pots 4–6 weeks before the average date of last frost.

The seeds require darkness to germinate so should be planted ½” deep in the soil. and 10–12” apart. Germination should occur a week to ten days depending on the soil temperature. They are climbers so will grow best in a location near a wall or trellis to encourage them to spread out.

Deadheading or picking the flowers will encourage blooming throughout the year. They prefer dry soils and will tolerate drought, they should be watered occasionally during the entire growing season to prolong blooming (16).

Nasturtium pesto

Nasturtium leaves and flowers are great wild edibles that are also easy to grow in the garden for easy all year round access to fresh greens. Their spicy, peppery bite makes for an excellent addition to pesto. You can either use a mix of basil and nasturtium leaves if you want more of a traditional pesto flavour or make a pesto with any combination of wild greens or nasturtiums simply as they are.

Ingredients

• 50 large nasturtium leaves (twice as many if small)
• ¼ cup pistachio, cashew or other nut
• ½ cup olive oil
• ½ cup parmesan cheese
• salt and pepper to taste

Method

• You may start by washing the nasturtium leaves. They can either be shaken dry in a salad spinner or gently patten with a kitchen towel (fine if they are slightly wet).
• Toast the nuts for a more earthy flavour. This can be done by placing them into a dry pan over medium heat, stirring every 30 seconds or so for 2–3 minutes. When they start to smell slightly toasted remove from the pan immediately.
  
• Fill your food processor up ¾ of the way, loosely, with leaves. Blend until they are chopped. Alternatively use a stick blender in a deep jug or bowl. Add more leaves, blend. Continue this until all of the leaves are blended up.
  
• The next step will be to add in the nuts and blend until finely chopped, then follow with the parmesan and half the oil. Continue to blend the ingredients together.
  
• Add more oil until it’s the desired consistency. This will highly depend on how much nasturtium and other greens have been used. 
  
• Add salt, black pepper, more nuts or more cheese to taste. The recipe is quite flexible and you can’t go too far wrong other than to not have enough oil to cover the blended material
• Store in a sterile container such as a jug. Keeping this in the fridge it can be eaten within a week.

1. The Medicinal Herb With an Antioxidant-Rich, Flavorful Kick. Dr. Axe. Accessed on 21.06.24. Accessed at: https://draxe.com/nutrition/nasturtium.
2. Marchyshyn S, Liliia Budniak, Liudmyla⃰. CHEMICAL COMPOSITION OF THE GARDEN NASTURTIUM ESSENTIAL OIL AND ANTIBACTERIAL ACTIVITY OF FRESH JUICE OF THE HERB. Archives • 2021 •. 3:1463-1473. Accessed June 21, 2024. https://pharmacologyonline.silae.it/files/archives/2021/vol3/PhOL_2021_3_A160_Marchyshyn.pdf
3. Menzies-Trull C. Herbal Medicine Keys to Physiomedicalism Including Pharmacopoeia. Newcastle, Staffs. Faculty Of Physiomedical Herbal Medicine; 2003.
4. Spiteri M. HERBAL MONOGRAPHS Including HERBAL MEDICINAL PRODUCTS and FOOD SUPPLEMENTS. https://core.ac.uk/download/pdf/237681409.pdf
5. Wood M. The Earthwise Herbal : A Complete Guide to Old World Medicinal Plants. North Atlantic Books; 2003.
6. Nasturtium. Forest Farm Peace Garden. Accessed on 25.06.24. Accessed at: https://www.forestfarmpeacegarden.org/blog/2020/7/14/nasturtium
7. Okoye TC, Uzor PF, Onyeto CA, Okereke EK. 18 – Safe African Medicinal Plants for Clinical Studies. ScienceDirect. Published January 1, 2014. https://www.sciencedirect.com/science/article/abs/pii/B9780128000182000182
8. Barrantes-Martínez YV, Liévano M, Ruiz ÁJ, et al. Nasturtium (Tropaeolum majus L.) sub-chronic consumption on insulin resistance and lipid profile in prediabetic subjects. A pilot study. Journal of Functional Foods. 2022;95:105189. doi:https://doi.org/10.1016/j.jff.2022.105189
9. Saba Rahimi Bahoosh, Yalda Shokoohinia, Eftekhari M. Glucosinolates and their hydrolysis products as potential nutraceuticals to combat cytokine storm in SARS-COV-2. Daru (Tehran Print). 2022;30(1):245-252. doi:https://doi.org/10.1007/s40199-022-00435-x
10. Plant Summaries—N. Georg Thieme Verlag eBooks. Published online January 1, 2004. doi:https://doi.org/10.1055/b-0034-55379
11. Mills SY. The Essential Book of Herbal Medicine. Editorial: Penguin; 1993.
12. Tran HTT, Márton MR, Herz C, et al. Nasturtium (Indian cress, Tropaeolum majus nanum) dually blocks the COX and LOX pathway in primary human immune cells. Phytomedicine. 2016;23(6):611-620. doi:https://doi.org/10.1016/j.phymed.2016.02.025
13. Bone, K., & Mills, S Principles and Practice of Phytotherapy: Modern Herbal Medicine (2nd ed.). Edinburgh Churchill Livingstone, Elsevier; 2013.
14. Therapeutic Research Center. Nasturtium. Natural Medicines, 2024. https://naturalmedicines.therapeuticresearch.com/databases/food,-herbs-supplements/professional.aspx?productid=455#interactionsWithDiseases
15. Williamson EM, Driver S, Baxter K. Stockley’s Herbal Medicines Interactions : A Guide to the Interactions of Herbal Medicines, Dietary Supplements and Nutraceuticals with Conventional Medicines. Pharmaceutical Press; 2009.
16. Nasturtium, Tropaeolum majus. Wisconsin Horticulture. Accessed June 21, 2024. https://hort.extension.wisc.edu/articles/nasturtium-tropaeolum-majus/#:~:text=Nasturtium%20has%20nearly%20circular%20leaves
17. Tropaeolum majus L. | Plants of the World Online | Kew Science. Plants of the World Online. https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:310974-2
18. The IUCN Red List of Threatened Species. IUCN Red List of Threatened Species. Published 2024. Accessed July 30, 2024. https://www.iucnredlist.org/search?query=Tropaeolum%20majus&searchType=species
19. Tropaeolum majus Garden Nasturtium | NatureServe Explorer 2.0. explorer.natureserve.org. Published May 7, 2024. Accessed July 30, 2024. https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.139255/Tropaeolum_majus
20. Species+. speciesplus.net. Accessed July 30, 2024. https://speciesplus.net/species#/