Calendula

What is Calendula?

Calendula officinalis is a short-lived aromatic herbaceous plant native to the Mediterranean and southwestern Asia, cultivated widely across Europe and North America. Its bright orange and yellow flower heads contain a complex array of bioactive compounds that give it potent wound-healing, anti-inflammatory, and antimicrobial properties. It has been used in European folk medicine, Ayurvedic practice, and modern integrative oncology for skin and mucosal conditions.

How does Calendula work?

Calendula's triterpenoids — particularly oleanolic acid and ursolic acid — inhibit pro-inflammatory mediators including cyclooxygenase (COX) enzymes and NF-κB signaling pathways, reducing local inflammation at wound sites. Its polysaccharides stimulate fibroblast proliferation and collagen deposition, accelerating tissue granulation and re-epithelialization. Flavonoids and carotenoids contribute antioxidant activity, reducing oxidative stress in damaged tissue, while saponins appear to enhance membrane permeability, improving absorption of active compounds.

What forms does Calendula come in?

Topical preparations (creams, ointments, gels) are the most clinically studied and widely used forms. Standardized creams typically contain 2–5% calendula flower extract. Tinctures (1:5 or 1:10 in ethanol) are used for oral rinses and diluted topical application. Oral capsules are available but have significantly less clinical trial evidence than topical forms. Calendula tea made from dried flower heads is used traditionally for gastric and mucosal complaints. For radiation dermatitis, a standardized aqueous cream formulation has been studied in oncology settings.

Where it comes from:

Calendula has been documented in European herbal medicine since at least the 12th century — referenced by Hildegard of Bingen — and used across Mediterranean, Arab, and Indian traditional systems for wound care, skin conditions, menstrual regulation, and digestive complaints. It was included in numerous European pharmacopoeias through the 19th and early 20th centuries and remains listed in the European Pharmacopoeia today. During the American Civil War, field surgeons used calendula poultices for wound healing and hemorrhage control, establishing its reputation as a battlefield botanical.

What does Calendula help with?

Calendula is a flowering plant in the daisy family. Many people know it as pot marigold. Its petals and flower heads have been used on the skin for hundreds of years.

Almost all the research puts calendula on the skin as a cream, or uses it as a mouth rinse. The library grade on file is B. That means at least one good human trial supports some uses, while others rest on much thinner ground.

• Skin burns and rashes from radiation therapy
  Good evidence — one randomised trial in 254 breast cancer patients. In a 254-person trial, calendula cream was compared with trolamine cream during breast radiation (Pommier and colleagues, 2004, Journal of Clinical Oncology). Grade 2 or worse skin damage was seen in 41% of the calendula group and 63% of the trolamine group (p<0.001). The calendula group also reported less pain during treatment.
  Evidence grade B · Traditional tier T2
• Wounds that are slow to close
  Good evidence — several small randomised and controlled trials in real wound care. In a number of small human trials, new skin formed faster with calendula than with petroleum-based creams. The clearest results came from wounds after childbirth, such as episiotomy and cesarean cuts. In lab work, plant compounds called triterpenoid saponins made skin-repair cells move and grow faster, and raised collagen.
  Evidence grade B · Traditional tier T2
• Healing after surgery or a cut from childbirth
  Good evidence — one controlled trial in women after episiotomy, plus earlier similar work. A controlled trial by Eghdampour and colleagues (2013, Journal of Caring Sciences) gave women calendula ointment after episiotomy. Their wounds closed faster and were less red than in the group given petroleum jelly. Earlier trials in similar groups pointed the same way.
  Evidence grade B · Traditional tier T2
• Mild to moderate eczema and contact rash
  Good evidence — one 72-person comparison trial against a steroid cream. In a 72-person randomised trial, calendula cream was compared with betamethasone valerate, a steroid cream (Panahi and colleagues, 2012, Journal of Wound Care). Calendula did about as well as the steroid, and had fewer side effect worries such as skin thinning. In lab studies, its flavonoids held back histamine release from mast cells.
  Evidence grade B · Traditional tier T2
• Diaper rash in babies
  Good evidence — one 66-infant randomised trial against aloe vera. A randomised trial in 66 newborns compared calendula ointment with aloe vera gel (Sharifi and colleagues, 2015, Breastfeeding Medicine). Rash scores dropped more in the calendula group at several check points. The trial was small and ran for a short time.
  Evidence grade B · Traditional tier T2
• Mouth sores from chemo or radiation
  Early evidence — one controlled study in head and neck cancer patients, size not on file. A controlled study by Badr and colleagues gave calendula mouthwash to head and neck cancer patients. Sores were less severe and did not last as long as with standard care, and the rinse was well tolerated. The number of patients is not recorded in our file, so this stays preliminary.
  Evidence grade C · Traditional tier T2
• Long-standing leg ulcers from poor vein flow
  Early evidence — small controlled trials and case series only. In small controlled trials and case reports, wound area shrank more with calendula than with standard dressings. No large trial has tested this. In tissue models, calendula supported new blood vessel growth and lowered germ counts.
  Evidence grade C · Traditional tier T2

What Calendula has not been shown to do

• The evidence here does not cover swallowing calendula as a tea or capsule; the studies used creams, ointments and mouth rinses.
• Calendula has not been shown to act on cancer itself, since the cancer trials looked only at skin and mouth side effects.
• It did not prevent all radiation skin damage; 41% of the calendula group in the 254-person trial still had grade 2 or worse.
• It has not been shown to work better than a steroid cream for eczema; the 72-person trial found it about equal.
• No human trial on file tested calendula against a diagnosed yeast (Candida) infection; that work is lab-level only.
• The leg ulcer evidence is too small to show calendula can stand in for standard wound care.

How to read this:

Each use has its own grade, based on the studies behind that use. A means several matching human trials. B means at least one good human trial. C means small or mixed human studies. D means weak or clashing human evidence. "Insufficient" means no human study at all. These are options to discuss, not advice, and not a promise of results. Talk to your doctor before using calendula on a wound, a baby's skin, or during cancer care.

What can Calendula help prevent?

• Prevention of grade 2+ acute radiation dermatitis in breast cancer patients undergoing radiotherapy (Pommier et al., 2004)
• Prevention of oral mucositis severity in patients receiving chemotherapy or head-and-neck radiation (emerging evidence, not yet definitive)

Which foods are rich in Calendula?

1. Calendula petals (edible, fresh or dried): The flower petals of Calendula officinalis are edible and are the direct source of all bioactive triterpenoids, flavonoids, and carotenoids; used as food coloring, in salads, and as tea — the most concentrated dietary form available.
2. Calendula herbal tea: Dried calendula flower heads steeped in hot water release water-soluble polysaccharides, flavonoids, and some saponins, providing a mild oral dose of active compounds; traditional preparation for mucosal and digestive support.

Practical Tips:

Calendula's therapeutic potency comes primarily from topical application or concentrated extracts rather than dietary intake. For individuals seeking to support the same skin and anti-inflammatory pathways through diet, foods rich in carotenoids (sweet potato, carrots, red bell peppers), quercetin (onions, capers, apples), and omega-3 fatty acids (fatty fish, flaxseed, walnuts) provide complementary anti-inflammatory and skin-supportive benefits. Avoiding pro-inflammatory foods — refined seed oils, excess sugar, ultra-processed foods — supports wound healing and reduces baseline skin inflammation.

What are the side effects of Calendula?

• Allergic contact dermatitis (in Asteraceae-sensitive individuals)
• Mild skin irritation or redness at application site (rare)
• Anaphylaxis in severe allergy cases (very rare, documented case reports)
• Mild sedation with high-dose oral use (theoretical, limited human evidence)
• Potential uterotonic effects with high oral doses: oral use not recommended in pregnancy beyond culinary amounts
• Gastrointestinal upset with high-dose oral supplementation (rare)

Good to know:

Calendula has an excellent safety record in both topical and oral use across centuries of human application and modern clinical trials. The most clinically significant risk is allergic contact dermatitis in individuals with Asteraceae plant family sensitivities, which affects a small but identifiable subset of the population. Oral use is less well-characterized but generally considered safe at typical herbal doses. Pregnancy safety for oral use beyond culinary amounts has not been established.

How much Calendula should you take?

• Recommended daily: Topical: Apply 2–5% calendula flower extract cream or ointment to affected area 2–3 times daily. Tincture (1:5): 1–4 mL diluted in water, used topically or as oral rinse 3 times daily. Oral capsules: 300–600 mg standardized extract daily (limited clinical data; follow product labeling). Calendula tea: 1–2 teaspoons dried flowers steeped in 250 mL hot water for 10–15 minutes, 2–3 cups daily.
• Best time of day: Topical application: Apply after cleansing the skin, ideally morning and evening. Oral tea or rinse: 2–3 times daily with or between meals for mucosal conditions.
• With or without food: Oral supplemental or tincture forms are generally better tolerated with food to reduce risk of GI discomfort. Topical use is not affected by food timing.
• Time to effect: Topical wound and inflammation: 5–14 days for visible improvement; oral mucosal effects: 3–7 days; radiation dermatitis prevention: effects seen over course of radiotherapy (weeks).
• How long to take it: Topical use for acute wound healing: continue until wound closure, typically 2–6 weeks. For radiation dermatitis: use throughout and up to 4 weeks post-radiotherapy. Long-term continuous oral use beyond 3 months lacks robust safety data; cycling or taking periodic breaks is prudent. Consult a healthcare provider for chronic skin conditions requiring extended use.