Marshmallow is the root or leaf of a member of the mallow family that grows in wet soils in much of Europe from England, Denmark, and central Russia south to the Mediterranean region. Escaped from gardens in North America, it grows in salt marshes from Massachusetts to Virginia and in the mountains of the western United States. The root is used to a greater extent than the leaves.
The genus name Althaea comes from the Greek altho, 11 associated with healing". Traditionally, Marshmallow root has been poulticed on bruises, muscle aches, sprains, burns, and inflammations. A tea of the leaves has been used to soothe sore throat and as an expectorant in bronchitis and whooping cough. Like many members of the mallow family, its tea is considered soothing to an upset stomach. Both the fresh and dried leaves have been used for similar conditions as the root but are considered somewhat weaker.
The leaves and root both contain mucilagin, the substance that makes the tea "slimy", considered the main active ingredient. The leaves contain up to 16 percent mucilagin, while the roots contain 25-30 percent.
Marshmallow preparations are recognized for their ability to soothe and soften irritated tissue, particularly mucous membranes, and to loosen a cough. Marshmallow also mildly stimulates the immune system. The German health authorities allow use of the leaf and root preparations to relieve local irritation and soothe irritated mucous membranes in sore throat accompanied by dry cough. Preparations of the root are also used to relieve local irritations, stimulate the immune system, slow down lung congestion in sore throat with dry cough, and relieve mild inflammation of the mucous membranes of the digestive tract.
Marshmallow root is generally available in the United States. Peeled root is considered of higher quality than root with the outer bark. The leaves are less familiar in America. The whole and cut-and-sifted root and powder are available in teas, capsules, and other formulations. In Europe, marshmallow syrups are available.
The mucilagin in marshmallow may absorb and hence reduce the action of drugs taken at the same time. In Germany marshmallow syrups (which are high in sugar) must be labeled as to sugar content so diabetics may be forewarned. Side effects are not reported for marshmallow.