Parts used: Bark, branches, leaves and berries. Scott Cunningham notes that the bark must be aged at least two years before using internally.
Medicinally Buckthorn was used similar to Syrup of Ipecac is today, as a purgative for children however due to the severity of the reaction it fell out of use with humans. Buckthorn has also been used as a laxative in the form of teas, tonics or syrups with sweet ingredients added to make it more palatable. In addition to its magical and medicinal properties, Buckthorn bark and leaves are used to make yellow dye to color fabrics and if collect before they ripen its berries, when mixed with gum-arabic and limewater, form the pigment 'Sap or bladder green" for water color painters.Scott Cunningham relays the following legend in his Encyclopedia of Magical herbs:It is said that if you sprinkle buckthorn in a circle and dance within it under a full moon, an elf will appear. The dancer must notice the elf and say "Halt and grant my boon!" before the creature flees. The elf will then grant one wish. Perhaps this will be part of my next full moon ritual, if I miss the elf at least I'll have fun dancing and he'll have fun watching from his hiding spot. Sources for this article:
Scott Cunningham's Encyclopedia of Magical Herbshttp://www.paganlore.comhttp://www.dragonherbarium.comwww.carolinadean.com