Demulcents and Emollients
Demulcents soothe, soften, and help heal any irritation of the mucous membranes. They contain slippery, mucilaginous properties, which in solution will coat the mucous membranes, shielding the tissues from irritating substances, and allowing healing to take place.
Emollient is the term for similar herbs used externally. Most demulcent herbs are also emollients, and when used in poultices they retain warmth and moisture while absorbing inflammation and infection.
Demulcents have a soothing action on the bowel from beginning to end. They can help protect the stomach and esophagus from acid and soothe inflammation in the entire bowel. Conditions such as heartburn, GERD, dyspepsia, indigestion, constipation diverticulitis may benefit from the action of demulcents.
The respiratory tree can be helped by the soothing action of demulcents to reduce dry coughs and sore throat. When taken internally for the urinary system, demulcents may be supportive in bladder inflammation, cystitis and the presence of urinary sand or stones.
Marshmallow - Althaea officinalis
Common names: Mallards, sweetweed, and cheese plant
Marshmallow is found in eastern North America in salty marshes, near riverbanks, and in moist shady soil. It can be cultivated elsewhere if watered adequately. Althea officinalis is not found naturalized in New Zealand or Australia. It is seen more frequently as a cultivated herb. However, several species of mallow are also very high in mucilage and can be used as a substitute for marshmallow. Malva sylvestris (large-flowered mallow) is found throughout New Zealand and Victoria. Malva parviflora (small-flowered mallow) is found throughout New Zealand and Australia. Malva moschata (musk mallow) is found throughout New Zealand, Tasmania, and Victoria.
Parts used: the root, leaves, and flowers
The root of marshmallow is particularly rich in mucilage, pectin, asparagine, sugars, tannin, lime, calcium, and cellulose. The flowers contain some mucilage, essential oil, sugars, and asparagine. The mucilage and asparagine are responsible for the demulcent and emollient actions. The mucilage also absorbs toxins and harmful micro-organisms in the system
Demulcent, diuretic, emollient, galactagogue, nutritive, and vulnerary
Burns, constipation, coughs, cystitis, diarrhea, hot flushes, inflamed eyes, inflammation (internal and external), kidney and bladder inflammation, lung tonic, skin abrasions, sore throats, stings, swollen joints, and promotes milk supply 
Marshmallow has been shown to have antibacterial effects against the bacteria responsible for periodontal disease, so a mouthwash made from marshmallow may be helpful. Large-flowered mallow M. sylvestris has been shown to have anti-complement activity. Complement is a major factor in inflammation, so this would make it a good anti-inflammatory.
Demulcents, or herbs that contain mucilage, have been used for many years for sore throats. They are not topical anesthetics but are soothing and relieve irritation. Herbs containing mucilage provide short-term relief of pain to people with acute pharyngitis. The effect does not last long—less than 30 minutes—so drink the tea frequently throughout the day
Precautions and contraindications:
Marshmallow is classed as safe for use when used appropriately. (The Commission E monographs state that absorption of other drugs taken simultaneously may be delayed, but they do not cite a reference. The high level of mucilage is most likely the cause for any delayed absorption.)
Preparation: cold extract, decoction, fluid extract, infusion, & poultice
Adult: All doses three to four times a day unless stated otherwise:
Cold extract: 2-T to 4-T
Decoction: 2-T to 4-T
Fluid extract: 2-ml to 5-ml
Infusion: 4-T to 6-T
Poultice: Apply as necessary
Administration: Use only under the direction of a trained herbalist familiar with the following formulations.
Burns, Inflammation, Swollen joints and Muscles - Prepare a poultice of the powdered root. Mix with slippery elm Ulmus rubra to increase effectiveness.
Constipation - Use the cold extract or infusion.
Coughs, Lung tonic, Sore throat - Use the decoction or prepare a syrup. A decoction of the flowers can be gargled for a sore throat.
Diarrhea - Use the powdered root in boiled milk.
Inflamed eyes - Bathe with the infusion prepared from the leaves and flowers.
Kidney and Bladder Tonic - Use the infusion or fluid extract.
Hot flushes and Promoting milk supply - Use the infusion or decoction or the root.
Stings (bee and wasp) - Remove stinger and rub with freshly bruised leaves.