Calendula (/kəˈlɛndjuːlə/), is a genus of about 15–20 species of annual and perennial herbaceous plants in the daisy family Asteraceae that are often known as marigolds.:771 They are native to southwestern Asia, western Europe, Macaronesia, and the Mediterranean. Other plants are also known as marigolds, such as corn marigold, desert marigold, marsh marigold, and plants of the genus Tagetes.The genus name Calendula is a modern Latin diminutive of calendae, meaning 'little calendar', 'little clock' or possibly 'little weather-glass'. The common name 'marigold' refers to the Virgin Mary.The most commonly cultivated and used member of the genus is the pot marigold (Calendula officinalis). Popular herbal and cosmetic products named 'calendula' invariably derive from C. officinalis. Calendula species have been used traditionally as culinary and medicinal herbs. The petals are edible and can be used fresh in salads or dried and used to color cheese or as a replacement for saffron. A yellow dye has been extracted from the flowers. Romans and Greeks used the golden calendula in many rituals and ceremonies, sometimes wearing crowns or garlands made from the flowers. One of its nicknames is 'Mary's Gold,' referring to the flowers' use in early Catholic events in some countries. Calendula flowers are sacred flowers in India and have been used to decorate the statues of Hindu deities since early times. Calendula ointments are skin products available for use on minor cuts, burns, and skin irritation; however, evidence of their effectiveness is weak. The flowers of C. officinalis contain flavonol glycosides, triterpene oligoglycosides, oleanane-type triterpene glycosides, saponins, and a sesquiterpene glucoside. Calendula oil is still used medicinally. The oil of C. officinalis is used as an anti-inflammatory and a remedy for healing wounds. Plant pharmacological studies have suggested that Calendula extracts have antiviral, antigenotoxic, and anti-inflammatory properties in vitro. In herbalism, Calendula in suspension or in tincture is used topically for treating acne, reducing inflammation, controlling bleeding, and soothing irritated tissue.Limited evidence indicates Calendula cream or ointment is effective in treating radiation dermatitis. Topical application of C. officinalis ointment has helped to prevent dermatitis and pain; thus reducing the incidence rate of skipped radiation treatments in randomized trials. Calendula has been used traditionally for abdominal cramps and constipation. In experiments with rabbit jejunum, the aqueous-ethanol extract of C. officinalis flowers was shown to have both spasmolytic and spasmogenic effects, thus providing a scientific rationale for this traditional use. An aqueous extract of C. officinalis obtained by a novel extraction method has demonstrated antitumor (cytotoxic) activity and immunomodulatory properties (lymphocyte activation) in vitro, as well as antitumor activity in mice.