Buckthorn bark is harvested from alder buckthorn, a small European tree now naturalized in North America.
Because the bark contains high levels of phenolic compounds it must be dried for a year before use, although ingestion of buckthorn tea or tincture can be toxic in large amounts. However, the bark can be used to make a yellow dye for paper, yarn and other textiles.
Safety:Vomiting may occur. If the Buckthorn bark is to be used, it should be dried from 1 to 2 years before use.