Buckthorn - Rhamnus frangula (in the Rhamnaceae or Buckthorn family)
Part used: Bark, aged a minimum of one year.
Taste/smell: Bitter, astringent.
Tendencies: Cooling, drying.
Dosage: Decoction: 1 heaping teaspoon per cup of water; or 1:5 dry plant liquid extract: 20-70 drops 1-4 times per day in a little water.
Use: (a) Laxative, (b) Cholagogue.
Most uses of buckthorn are due to its laxative effect. It acts on the large intestine to stimulate peristalsis and increase secretion of water into the large intestine lumen making it specific for chronic constipation with hepatic sluggishness. It is also used with anal fissures, hemorrhoids and after rectal operations.
The constituents in this herb are activated by intestinal flora. The bark contains anthraquinone glycosides, including emodin and frangulin. Buckthorn has about half the amount of emodin found in Cascara. Research with animals has shown emodin to possess anticancer, antibacterial, diuretic, immunosuppressive, and vasorelaxant activities.
Contraindications: Do not use for extended periods of time. Chronic use will deplete electrolytes, especially potassium, bringing about muscle weakness and paralysis of intestinal musculature, making the laxative less effective, promoting constipation and thus requiring more of the laxative to be used.
Potassium loss can disturb cardiac rhythm and potentiate cardiac glycoside toxicity. Herbs with cardiac glycosides include pheasant's eye (Adonis), lily of the valley (Convallaria), fox glove (Digitalis), false hellebore (Helleborus), Strophanthus and Urginea. Physicians should closely monitor individuals who consume formulas with anthraquinones while taking cardiac glycosides.
An overdose or overusage of anthraquinones may cause vomiting, intestinal spasms and bloody diarrhea. An overdose may cause kidney inflammation. This herb, as with all laxatives, should not be used in cases of intestinal obstruction when there is danger of an intestinal rupture. Any herb containing anthraquin-ones should not be consumed by pregnant women or nursing mothers because it can be passed through breast milk to the baby. It is also contraindicated in abdominal pain of unknown origin and children under the age of 12 due to loss of water and electrolytes. Emodin has also been reported to be a mutagen in a few experiments.