Calendula is an annual herb native to southern Europe and the eastern Mediterranean, naturalised in many parts of the United States. The uses of Calendula for horses are set out below.
A fast growing bushy annual with an angular branched stem and a pithy hollow core 30 –60cm high. The leaves are pale green, lance shaped, sticky and strongly aromatic. The plant has single daisy-like flowerheads, bright orange in colour with ligulate florets 13 – 25mm long and about 3mm broad.
So named from Latin Calends, meaning the first day of the month, because it flowers continuously from May to October.
It is believed that it originated in Egypt and was used as a rejuvenating herb.
During the American Civil War, field doctors used Calendula leaves to dress surgical wounds with documented success.
Medicinal Uses of Calendula for Horses
For medicinal purposes, the leaves, whole flowerheads or petals alone are used. Only the deep orange varieties have the carotenoid lutein present in the petals, giving antioxidant and tissue forming medicinal qualities.
Calendula is the herb of choice for wounds and bruising. Traditionally known as ‘the homoeopathic antiseptic’, wounds treated with calendula extracts healed cleanly and rapidly without one drop of pus. It has the following properties:
This has been recently backed up by research confirming Calendula’s anti-bacterial properties against Staphylococcus aureus and Streptococcus faecalis both commonly found on the skin and in the nares and throat, using a dry hydroethanolic extract.
As with all natural herbs, care must be taken with their administration to horses – see below
Bags of Calendala (Marigold) can be purchased cheaply, with the knowledge that it is the right sort of Marigold and with feeding instructions
Compresses soaked in 90% tincture can be used to staunch bleeding. The 90% tincture is used neat or diluted with an equal part of previously boiled cold water to disinfect wounds and stitching.
Ointment containing 5% calendula oil or tincture is used to promote rapid healing with granulation and epithelization of new tissue. This is mainly due to the carotenoid pigments in lutien found only in the deep orange petals of Calendula officinalis, the other garden varieties lack this quality. Recent studies confirm the medicinal activity. Note 
Infused calendula oil with added tea tree can be used as a hoof oil to treat infection of the frog, particularly thrush. The anti-fungal properties also make calendula oil, an useful addition to ointments for mud fever.
Infusion: 30gms of petals and leaves to a pint of boiling water, steep 15 minutes, then strain. Use cold as a local application for bruising and swelling. Calendula assists local action and prevents suppuration.
Decoction: Calendula petals for inflamed gritty and sore eyes . Using a stainless steel pan take 30gms of the petals, add 500mls water, bring to the boil, simmer 10 minutes, strain and cover. Leave to cool. Use cold to bathe the eyes.
Herbal Wound Glue” 1:5 90% alcohol using flowerheads and leaves to extract the resinous qualities. The resinous fraction being ‘herbal wound glue’ to mend wounds, seal inflamed surfaces and suffocate bacteria. Use neat on wounds and sores as an antiseptic. Dilute with an equal part of water to use for internal bacteria.
Flower petals in 1: 5 25% alcohol. This is used internally as an immune stimulant and anti-oxidant, stimulates the liver into bile production, mild oestrogens help regulate irregular seasons in mares.
Fresh flowerhead or leaf / juice: can be rubbed straight onto midge bites and bee stings for instant relief.
Cautions: Do not confuse Pot marigold (Calendula species) with the French marigold (Tagetes patula) or the African marigold (Tagetes erecta) both species of Tagetes are used as insecticides and weed killers.
Calendula for horses is often combined with Cleavers as a tonic and to support the lymphatic system.
 Dumenil G et al., Evaluation of antibacterial properties of marigold flowers (Calendula officinalis) and mother homeopathic tinctures of Calendula officinalis Re: Annual Pharm French 1980
 The anti-inflammatory activity has been demonstrated in two studies of mice Akihisa et al., 1996 Triterpene alcohols from the flowers of Compositae and their anti-inflammatory effects.
 Zitter-Eglseer et al., 1997 Anti-oedematous activities of the main trierpenoid esters of marigold ( Calendula officinalis)
 Surgically induced wounds treated with an ointment containing 5% calendula extract showed marked physiological regeneration and epithelialization Klouchek-Popova et al., 1982 Influence on Physiological Regeneration and Epithelization Using Fractions Isolated from Calendula Officinalis
British Herbal Compedium Vol 2 – 2006
Professional Handbook of Complementary & Alternative Medicines – Charles Feltrow, Pharm D Juan R.Avila, PharmD