The bark contains a host of other constituents, but the carbohydrates that comprise the mucilage are the most important. The mucilage appears to act as a barrier against the damaging effects of acid on the esophagus in people with heartburn . It may also have an anti-inflammatory effect locally in the stomach and intestines. Test tube studies in Korea on a related tree found it was anti-inflammatory. 3 Clinical research verifying these mechanisms of action has not been conducted.
Slippery elm is also an ingredient of some cough lozenges and cough syrups.
Slippery elm is quite safe. However, because it is so mucilaginous, it may interfere with the absorption of medicine taken at the same time. At the time of writing, there were no well-known drug interactions with slippery elm. For the convenience of the reader, the information in the table listing the supplements for particular conditions is also categorized. CRC Handbook of Medicinal Herbs .