The marshmallow is a confection that, in its modern form, consists of sugar or corn syrup, beaten egg whites, gelatin that has been pre-softened in water, gum arabic and flavorings, whipped to a spongy consistency. The traditional recipe used an extract from the mucilaginous root of the marshmallow, a shrubby herb (Althaea officinalis), instead of gelatin; the mucilage performed as a cough suppressant.

GoldBamboo

... Marshmallow root and — to a lesser extent — marshmallow leaf both contain significant percentages of mucilage, a natural gummy substance that does not dissolve in water. Like other mucilage-containing substances, marshmallow swells up and becomes slick when it is exposed to fluids. The resulting slippery material coats the linings of the mouth, throat, and stomach to relieve irritation and control coughing associated with respiratory or stomach conditions. For example, marshmallow has been used to treat sore throats and to alleviate heartburn. Marshmallow may also have mild anti-infective and immune-boosting properties, but further study is needed to confirm these possible effects. ...
Drug Digest - more...

For the confection, see marshmallow. ?Althaea Marshmallow (Althaea of ...
Wikipedia - [full article]

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