I believe it is referring to the healing properties of the mallow plant.
http://www.planetbotanic.ca/fact_sheets/marshmallow_fs.htm
Scientific Name: Althaea officinalis
Part Used: Root
In a word: Skin soother
Uses: Irritated Skin
If you are thinking that I am about to suggest applying marshmallows to your irritated skin, you are right. It is a little-known fact that marshmallows, now made of sugar and gums, were once made from a plant called the marshmallow plant. Marshmallows are an old-time confection, and their main ingredient originally was a mallow plant that is inclined to grow – guess where – in the marsh. Its roots contain a large quantity of a very slimy substance called mucilage. Several centuries ago, a very chic dessert called pate de guimauve was made by grinding the root and adding the resulting powder to beaten egg whites and sugar. The end result, served at many a royal dinner, was also known as marsh-mellows. In time, the ground marshmallow root in the confection was replaced by animal gels and gums. Today, there is hardly a natural ingredient in those sticky sweets found at the grocery store, but this wasn’t always the case.
Though we no longer use marshmallow root in candy making, herbalists have always used and continue to use marshmallow to sooth irritated tissue, whether inside or outside the body. The plant is native to Europe, but it can now be found growing in most moist spots worldwide.
If you have a wound that won’t heal, a wound that you want to heal quickly, or a patch of skin that is giving you a problem, laying some marshmallow on it will get the healing process going.
The marshmallow belongs to a very slimy group of plants, the mallow family, which includes okra, cotton, hibiscus, and hollyhock. The common denominator with these plants is their production of a viscous slime. If you have ever eaten okra, or bindi as it is called in Indian cuisine, you are familiar with the substance in question. One thousand species of mallows have been discovered around the globe, and all have this slimy quality to a greater or lesser degree.
The mucilage in mallow plants is a complex sugar composed of a number of polysaccharides. One of these is made up of 1-rhmanose, d-galactose, d-galacturonic acid, and d-glucuronic acid. The structure of the polysaccharides contained in marshmallow is such that they cannot be digested by the human body. Beyond polysaccharides, the root contains pectin, asparagine, and tannins.
Marshmallow is the most famous of the mallow family for soothing irritated tissues. The indigestible nature of its mucilage means that when you are taking marshmallow for internal irritations, the slime will slither its way down the entire digestive tract, soothing as it goes and guaranteeing relief from top to bottom.
The leaves of the marshmallow plant as well as the root are used as medicine. Marshmallow leaves are of a slightly different chemical makeup. They contain the same mucilage as the roots, but they also come packing flavonoids including kaempferol, quercetin, and diosmetin glucosides; additionally, the leaves contain the coumarin scopoletin and phenolic acids including syringic acid, caffeic acid, salicylic acid, and vanillic acid.
We aren’t’ really accustomed to putting many slimy things in our mouths, and as such, vegetables like okra have a limited following. Though our palates may have a problem with the consistency, our tissues love the stuff. The internal uses of marshmallow include healing irritated respiratory, digestive, and urinary systems, where it acts as a soothing anti-inflammatory. Here, however, our concern is the skin.
When it comes to the skin, marshmallow has been used to treat abscesses, boils, varicose veins, ulcers, inflammations of the mouth and throat, inflamed hemorrhoids, wounds, burns, scalds, and bedsores. One of the most famous uses for marshmallow is in "drawing creme," so-called because when a paste of marshmallow and slippery elm is applied to a splinter, thorn, or even a bee stinger, the cream will almost miraculously draw out the offending item and speed the