Calendula

Calendula officinalis

Family: Asteraceae Part used: Flowers

Key Compounds

• Oleanolic acid glycosides
• Oleanane-type triterpene saponins
• Ursolic acid
• Alpha-amyrin
• Beta-amyrin
• Luteolin
• Quercetin
• Isorhamnetin
• Hyperoside
• Rutin
• Narcissin
• Carotenoids (lutein, zeaxanthin, beta-carotene)
• Lycopene
• Calendulin
• Polysaccharides

Traditional Use

• Radiation dermatitis prevention — 2004 Pommier et al. RCT (Journal of Clinical Oncology): 254 breast cancer patients undergoing radiotherapy; calendula cream was significantly superior to trolamine cream (standard pharmaceutical comparison) in preventing acute dermatitis and was rated more soothing; this is the strongest single clinical trial for any topical calendula application
• Wound healing — triterpenoid saponins and flavonoids stimulate fibroblast migration and proliferation in cell studies; the mechanism involves enhanced collagen synthesis and epithelialisation; used topically across European, Middle Eastern, and South Asian traditions for cuts, burns, and skin irritation with continuous documentation from the 12th century
• Anti-inflammatory — flavonoids (luteolin, quercetin, isorhamnetin) inhibit COX-2 and NF-κB; triterpenoids inhibit complement system activation; clinical and laboratory basis for traditional use in inflammatory skin conditions
• Traditional cooking and dyeing — dried petals used as yellow-orange food dye in rice, butter, soups, and pastries throughout Mediterranean Europe and the Middle East; an inexpensive saffron substitute in some traditions; petals used to dye textiles and cheese; edible petals still used in contemporary cooking
• Digestive tract support — traditional European use for gastric ulcers, gastritis, and intestinal inflammation; the anti-inflammatory and mucosal-healing properties have laboratory support; German Commission E approved for oral and pharyngeal inflammation
• Historical wound use — documented in 12th century German medicine by Hildegard of Bingen; widely used in European wars including the American Civil War and both World Wars as wound dressing; calendula cream used by military surgeons as antiseptic and anti-inflammatory dressing

The name means calendar.

Pliny the Elder wrote that calendula flowered on the calendae — the first day of each Roman month. This was slightly exaggerated. What he was actually observing was that the plant flowers continuously and reliably across its entire season, from late spring to first frost, without gaps. It blooms on the first of the month and the last. It is simply always flowering.

The name has stayed for over two thousand years. The reliability has stayed with it.

Meet the plant

An annual or short-lived perennial herb, 30–60 cm tall, with sticky aromatic leaves and bright orange to yellow composite flower heads 4–7 cm across. The flowers are harvested repeatedly throughout the season — the more you pick, the more it produces. It is one of the most generous flowering plants in a garden.

It grows easily in poor-to-medium soil in full sun. It has been in continuous cultivation around the Mediterranean for over 2,000 years.

Not the same as marigold

This requires immediate clarification.

‘Marigold’ in common usage refers to two completely different plants. Calendula officinalis — pot marigold, English marigold — has documented medicinal use going back two millennia and extensive clinical evidence. Tagetes species — African marigold, French marigold — are ornamental garden plants in a completely separate genus with different chemistry and no equivalent medicinal tradition.

The confusion is common enough to be dangerous in supplement and cosmetic product purchasing. When a product specifies calendula, it should contain Calendula officinalis. Tagetes products are not interchangeable.

The easiest distinction: Calendula has sticky, aromatic leaves and produces flowers continuously. Tagetes has divided leaves and is not sticky. They look similar. They are different plants.

Three uses in the same flower

The same plant has been used simultaneously, by the same civilisations, for three completely distinct purposes.

Wound healing. Documented from the 12th century in Hildegard of Bingen’s medical writings. Used in the American Civil War and both World Wars as wound dressing. The triterpenoid saponins stimulate fibroblast migration and collagen synthesis — the cell biology of wound repair. The flavonoids reduce wound inflammation. The effect is real.

Food colouring. Dried petals yellow-orange rice, soups, butter, and pastries throughout Mediterranean Europe and the Middle East. Called ‘poor man’s saffron’ in some traditions for the colouring effect at lower cost. The petals are edible — used fresh in salads, as garnishes, steeped in cream.

Textile dyeing. The same carotenoid pigments that colour food and wound tissue colour fabric. Wool and linen dyed with calendula in traditional European practice.

Three applications, one plant. This is what economic botany looks like before specialisation.

The radiation dermatitis trial

The 2004 Pommier et al. RCT, published in the Journal of Clinical Oncology, enrolled 254 breast cancer patients undergoing radiotherapy.

Half received calendula cream. Half received trolamine cream — the standard pharmaceutical treatment for radiation-induced skin damage, a petroleum-based emollient with anti-inflammatory properties.

Primary outcome: acute Grade 2 or higher dermatitis.

Calendula group: 41% incidence. Trolamine group: 63% incidence. Statistically significant.

The calendula group also rated their treatment as significantly more comfortable.

This is a well-designed trial with a direct pharmaceutical comparison in a clinical population. It is the strongest single piece of clinical evidence for topical calendula — an herbal preparation significantly outperforming a standard medical treatment for a specific outcome.

The chemistry

Triterpenoid saponins: Oleanolic acid glycosides and related compounds are the primary wound-healing constituents. They stimulate fibroblast activity, increasing collagen production and tissue repair. Concentration is highest in the resin glands on the phyllaries (the green bracts around the flower base).

Carotenoids: Beta-carotene, lutein, zeaxanthin, lycopene — the orange-yellow pigments responsible for the flower colour and significant anti-inflammatory activity.

Flavonoids: Luteolin, quercetin, isorhamnetin, rutin — COX-2 inhibition, NF-κB modulation, antioxidant activity.

What people actually do with it

Topical cream or salve (primary use): Applied to minor wounds, burns, radiation skin damage, eczema, nappy rash, and dry skin. Available commercially as standardised extracts. Applied 2–3 times daily to affected areas.

Infused oil: Flowers infused in carrier oil (olive or jojoba) for 4–6 weeks, then strained. Used as a base for homemade salves or applied directly as a massage oil for dry skin.

Tea (internal use): 1–2 teaspoons dried flowers, steeped 10 minutes, 2–3 cups daily. Traditional use for gastritis, gastric ulcers, and intestinal inflammation. German Commission E approved for oral and pharyngeal inflammation.

Gargle: Strong calendula tea used as a gargle for sore throat and gum inflammation.

Culinary: Fresh petals in salads, as garnish, or steeped in cream. Dried petals as food colouring and mild flavouring in rice and soups.

Could you grow this yourself?

Easily. Calendula grows in almost any soil in full sun. Sow directly where it is to grow, in spring or autumn (it prefers cool temperatures for germination). It self-seeds freely in mild climates and will appear reliably year after year without replanting.

Harvest the open flower heads regularly throughout the season — this encourages continuous new flower production. Dry quickly at low temperature. The sticky resin on the phyllaries is a good indicator of potency: freshly dried flowers should feel slightly tacky when handled.

Calendula (キンセンカ) in Japan

キンセンカ (kinsenka, ‘gold-coin flower’) is a popular garden plant throughout Japan, grown primarily as a winter-to-spring flowering annual in milder regions (it dislikes Japan’s summer heat and humidity). It is widely available at garden centres.

Topical calendula preparations are available in Japanese pharmacies and supplement retailers, positioned for skin care rather than wound healing in most marketing. The radiation dermatitis evidence is known in Japanese oncology nursing contexts.

Japanese traditional medicine has no classical relationship with calendula. It is not a kampo ingredient. The plant arrived in Japan via European ornamental horticulture, and the medicinal use has followed through the supplement and cosmeceutical market rather than through traditional practice.

The kitchen use is not part of Japanese food tradition in the way it is Mediterranean. The flowers are grown for the garden.

Things you’re probably wondering

What was the radiation trial? 254 breast cancer patients, calendula cream vs trolamine cream, during radiotherapy. Calendula: 41% Grade 2+ dermatitis. Trolamine: 63%. Significant superiority. 2004, Journal of Clinical Oncology.

Is it the same as marigold? No. Calendula = Calendula officinalis. Marigold = Tagetes. Different genus, different chemistry, not interchangeable. The confusion is common and matters for product purchasing.

Why is it good for wounds? Triterpenoid saponins stimulate fibroblast migration and collagen synthesis. Carotenoids and flavonoids reduce inflammation. Multiple converging mechanisms for tissue repair.

Is it safe? For most people, topically, yes — it is among the safer topical herbs. Main exception: Asteraceae family allergy.

Botanical details

The full compound list

See Also

• Chamomile — fellow Asteraceae anti-inflammatory; complementary for skin and digestive conditions
• Yarrow — wound herb from same family; haemostatic and anti-inflammatory
• St. John’s Wort — another traditional wound and skin herb with strong clinical evidence

References

• Pommier, P. et al. (2004). Phase III randomized trial of Calendula officinalis compared with trolamine for radiation dermatitis. Journal of Clinical Oncology, 22(8), 1447–1453.
• Fronza, M. et al. (2009). Determination of the wound healing effect of Calendula extracts. Journal of Ethnopharmacology, 126(3), 463–467.
• Butnariu, M. & Coradini, C.Z. (2012). Evaluation of biologically active compounds from Calendula officinalis flowers. Chemistry Central Journal, 6, 35.
• Leach, M.J. (2008). Calendula officinalis and wound healing. Wounds, 20(8), 236–243.