Marigold (Calendula officinalis) is an herb that has centuries of use for its health benefits and culinary attributes. It is widely distributed worldwide and is commonly referred to as pot marigold (a reference to how easy it is to grow in containers). Keep in mind that there are over 20 different named species in the calendula group (genus), but it is the C. officinalis that is used for medicinal and food purposes. This is not the same as the garden marigold (Tagetes sp.).
The calendula flowers are used for both medicinal and culinary purposes. From a culinary perspective, the flowers are used to add flavor to foods and yellow to orange color for foods like butter, cheeses, custards and rice dishes.
It is always interesting to review the historical use of an herb, because this provides insights into its potential benefits. Often modern research techniques validate these uses and identify the important active factors in the herb. For calendula, historical medicinal use has been for both external and internal issues. Common external uses have focused on skin issues like wounds, abrasions, bruises and superficial burns. The properties that make calendula useful for skin issues make it valuable for some internal health problems. Internally, it has been used for issues like stomach ulcers, liver problems and internal inflammatory disorders. It has also been used as a rinse for mouth and throat inflammatory conditions.
Calendula continues to be used because of the beneficial effects that are observed. Interestingly, modern research is confirming that calendula has a wide range of effects including anti-inflammatory, antimicrobial and astringent properties that contribute to its ability to promote healing. Astringents firm the tissue and reduce excessive discharge, which facilitates healing. Some clinical studies have shown increased healing of experimental excision wounds and skin ulcer reduction almost three times better than control treatments. Certain compounds in calendula, like rutin and quercetin, are thought to stimulate specific cellular targets that increase wound healing activity. Other studies have demonstrated benefits for managing gingivitis and periodontal disease. Models investigating the effect of calendula on stomach ulcers show a benefit. Calendula appears to have the ability to effect the rate of stomach emptying, lower blood sugar, and protect the liver and kidneys against toxic insults.
Keep in mind that the effects of herbs, like with medications, is dependent on the dose and contact time with the tissue. The extraction process (ie tincture vs infusion) and formulation of the product can influence its effectiveness. Selection of the product depends on the intended use, because there are many ways to use calendula. Available product forms include tinctures, infusions, creams, gels, salves and ointments. Tinctures are made using a described process that involves soaking the dried flowers in alcohol (or glycerine) for a defined period of time, then removing the flower material. The tincture can be administered orally for internal use or used in preparations like creams and ointments. Sometimes it is desirable to avoid alcohol. Alcohol affects the taste of the product, raises concerns about alcohol consumption and can sting when applied topically. Avoiding the alcohol can be done by allowing the alcohol to dissipate before use, using a glycerine based product or using an infusion. Infusions (like making tea) can be made from calendula and applied to injured skin. Infusions using oils like olive oil can also be made.
Selecting a product involves using a source that is reliable, because it is relatively easy to have adulterated herb products. This makes purchasing from quality sources critical.
Calendula is considered safe for topical and internal uses for dogs and cats, but it should be avoided during pregnancy. It is also valuable to be aware that calendula is a member of the aster family. Allergy to the aster family is a common concern in humans, but the frequency is unknown in pets. If redness, irritation or itching occur after topical use, the calendula should be discontinued.
Calendula is an interesting herb with long historical use in a wide range of situations. It appears safe in pets for topical uses. For internal use, consultation with a veterinary herbalist is recommended.
Ron Carsten, DVM, PhD, CVA, CCRT was one of the first veterinarians in Colorado to use the integrative approach, has lectured widely to veterinarians, and has been a pioneer in the therapeutic use of food concentrates to manage clinical problems. He is also the founder of Colorado Animal Rescue (CARE). In addition to his Doctor of Veterinary Medicine, he holds a PhD in Cell and Molecular Biology and is a Certified Veterinary Acupuncturist and Certified Canine Rehabilitation Therapist. He practices integrative veterinary medicine in Glenwood Springs.