Calendula

Common names: Marigold, Pot marigold

Botanical name: Calendula officinalis

Parts used and where grown

Calendula grows as a common garden plant throughout North America and Europe. The golden-orange or yellow flowers of calendula have been used as medicine for centuries.

Calendula has been used in connection with the following conditions (refer to the individual health concern for complete information):

Rating	Health Concerns
	Dermatitis (radiation-induced)
	Breast-feeding support (topical for sore nipples) Burns (minor) Conjunctivitis/blepharitis Eczema Peptic ulcer Poison ivy and poison oak dermatitis Ulcerative colitis Wound healing (topical)
Reliable and relatively consistent scientific data showing a substantial health benefit. Contradictory, insufficient, or preliminary studies suggesting a health benefit or minimal health benefit. For an herb, supported by traditional use but minimal or no scientific evidence. For a supplement, little scientific support and/or minimal health benefit.

Historical or traditional use (may or may not be supported by scientific studies)

Calendula flowers were historically considered beneficial for reducing inflammation, wound healing, and as an antiseptic. Calendula was used to treat various skin diseases, ranging from skin ulcerations to eczema.¹ Internally, the soothing effects of calendula have been used for stomach ulcers and inflammation. Traditionally, a sterile tea was topically applied in cases of conjunctivitis.

Active constituents

Flavonoids, found in high amounts in calendula, are thought to account for much of its anti-inflammatory activity.² Other potentially important constituents include the triterpene saponins³ and carotenoids.

Investigations into anticancer and antiviral actions of calendula are continuing. At this time, insufficient evidence exists to recommend the use of calendula for cancer. Nevertheless, test tube studies have found antiviral activity for calendula.⁴ ⁵ The constituents responsible for these actions are not clear, however, and the relevance of these actions for human health care has not been established.

How much is usually taken?

A tea of calendula can be made by pouring 1 cup (250 ml) of boiling water over 1–2 teaspoons (5–10 grams) of the flowers; the tea is then steeped, covered for ten to fifteen minutes, strained, and drunk.⁶ At least 3 cups of tea are recommended per day. Tincture is similarly used three times a day, at 1/4–1/2 teaspoon (1–2 ml) each time. The tincture can be taken in water or tea. In addition, prepared ointments can be used topically for skin problems, although wet dressings made by dipping a cloth into the cooled tea are also effective. Topical treatment for eye conditions is not recommended, as absolute sterility must be maintained.

Are there any side effects or interactions?

Side effects are rare with the use of calendula. Some people may experience a skin rash with topical use and should be tested to see if they are allergic to the herb.

At the time of writing, there were no well-known drug interactions with calendula.

References

1. Leung A, Foster S. Encyclopedia of Common Natural Ingredients Used in Food, Drugs and Cosmetics, 2d ed. New York: John Wiley & Sons, 1996, 113–4.

2. Weiss RF. Herbal Medicine. Gothenburg, Sweden: Ab Arcanum, 1988, 344.

3. Della Loggia R, Tubaro A, Sosa S, et al. The role of triterpenoids in the topical anti-inflammatory activity of Calendula officinalis flowers. Planta Med 1994;60:516–20.

4. Bogdanova NS, Nikolaeva IS, Shcherbakova LI, et al. Study of antiviral properties of Calendula officinalis. Farmskolto Ksikol 1970;33:349–55 [in Russian].

5. De Tommasi N, Conti C, Stein ML, et al. Structure and in vitro activity of triterpenoid saponins form Calendula arvensis. Plants Med 1991;57:250–3.

6. Wichtl M. Herbal Drugs and Phytopharmaceuticals. Boca Raton, FL: CRC Press, 1994, 118–20.

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The information presented in Healthnotes is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or chemist for any health problem and before using any supplements or before making any changes in prescribed medications. Information expires September 2008.