The flower "calendula officinalis" has been used medicinally in Europe since the 12th century. In Egypt it has been used even earlier, especially for skin conditions. The herb is used primarily to treat itchy skin, boils or minor wounds. It helps to heal skin infections, burns, cuts, punctures or scrapes.
I got acquainted to calendula in my early childhood. My grandmother in Israel who lived in our home used this flower to treat itchy skin. The flower is also popular in central Europe. I encountered it in the alps of Switzerland, where it is called "Ringelblume". In the US, the herb is also known as "garden marigold" and is popular as a garden flower.
Calendula has a high concentration of flavonoids which act as antioxidants in the body. It also contains triterpenoids which have anti-inflammatory benefits and are also responsible for Calendula's antiviral properties. Calendula contains carotenes and carotinoid pigments, as well as a small quantity of volatile oil. Its wound-healing power is best used together with other flowers like Arnica but Calendula alone is always well tolerated.
Why does it work? From the western medicine point of view, Calendula increases granulation at the site of the wound. It promotes metabolism of proteins and collagen. In other words the herb helps to grow new healthy cells.
From the Chinese medicine point of view Calendula is "neutral". It is a "drying herb" that "releases exterior wind heat" and "invigorates the blood". In the language of Chinese medicine, skin conditions are related to "pathologies involving the liver and the lung". Skin conditions in the summer arise from invasion of "wind heat" to the skin that causes "stagnation of blood". Calendula removes the stagnation allowing the blood to nourish the skin. It also "cools and releases the wind". Note that in Chinese medicine, "wind" is a pathogen concept.
The dosing industry standard is to use a 2-5 percent ointment 3-4 times per day. This corresponds to 2-5 gram of dried flower in 100 grams of ointment. In severe cases, a 10 percent concentration ointment can be used.
In the summer, I dry Calendula flowers from my garden and use an infusion for which I take 2 table spoons of dried flower together with 1/2 liter of boiling water to use as a compress for skin treatment.
Producing a salve requires more work: I mix the dried flowers with olive oil, where I use twice the amount of oil than flower in volume. Then I let it rest for 6 weeks so that the oil captures the essences of the herb. After that, I filter the flower out and mix the oil with 1/4 volume of bees wax and add some coconut oil for additional skin benefits. Then I mix all together thoroughly while heating it up. The salve can be used after it has cooled.