Both the root and the leaf of the marshmallow plant contain a substance known as mucilate, a mucusy substance that does not dissolve in water. It is this substance that causes marshmallow to swell up and become slippery when wet. This attribute of the marshmallow plant gives it the ability to soothe irritation of the mouth, throat and stomach, as well as to relieve coughing. Marshmallow is also believed to have a limited ability to fight infection and boost the immune system. While the effectiveness of marshmallow has not been substantiated by human pharmalogical studies, it has been used in connection with: * Asthma * Common cold/sore throat * Cough * Crohn's disease * Diarrhea * Gastritis * Gastroesophageal reflux disease (GERD) * Indigestion * Pap smear (abnormal) * Peptic ulcer * Ulcerative colitis