Slippery elm is a tree from eastern Canada and the central United States that has broad leaves. It is the inner bark that is used for medicinal purposes.

Slippery elm benefits:

Current data is insufficient to classify it. Some people use it for gastrointestinal and urinary problems. It is also used topically for some skin problems.

Slippery elm side effects :

Although it is generally well tolerated, some people report the following side effects: contact dermatitis

Pregnancy and breast-feeding: 

Avoid, as current data are insufficient to ensure its safety.

Reference:

https://naturalmedicines-therapeuticresearch-com.acces.bibl.ulaval.ca/databases/food,-herbs-supplements/professional.aspx?productid=978