Commission E endorses marsh mallow, hollyhock and other mallows for cough and sore throat . It adds something extra to the soup's cold-relieving benefits. A tea made with mullein flowers provides throat-soothing mucilage and also has an expectorant effect. The plant reportedly contains compounds that inhibit flu viruses. I have had good success with mullein leaf teas as well.
Commission E recommends seneca snakeroot as an expectorant for reducing upper respiratory phlegm.
To make a tea, use about one teaspoon per cup of boiling water. Finally, the Food and Drug Administration got something right. It has declared slippery elm a safe and effective throat and respiratory soother. Slippery elm was a medical mainstay in this country for more than 150 years and was long listed in the nation's official guides to therapeutics. The bark contains large quantities of a mucilage that acts as an effective throat soother and cough suppressant.