Buckthorn Bark

Rhamnus frangula

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.

Buckthorn has a wide distribution in Europe, Asia and the Middle East. In North America, however, where it is now naturalized, it is considered an invasive species, especially in the eastern and central regions of the United States. In fact, the sale or import of the seedlings of this species is specifically prohibited in Minnesota and Illinois.

The wood of this shrub is used to make fuses and gunpowder and, at one time, to make the forms used by shoemakers. Buckthorn bark is harvested in summer and is then aged or heat-treated before it's ready for consumption. This process breaks down the anthrone chemicals in the bark and its action from strongly purgative to laxative. The bark is also used to produce dyes for wool and other textiles. These traditional uses of buckthorn bark give rise to additional alternative names, such as purging buckthorn and dyer’s buckthorn.

Although buckthorn bark can be prepared as tea, it is more commonly tinctured or encapsulated due to its bitter taste.