Botanical Overview
Rhamnus purshiana (cortex), commonly known as Cascara sagrada or Sacred bark, belongs to the family Rhamnaceae. The medicinal part used is the bark harvested primarily from this species native to North America, especially the Pacific Northwest region.
Energetics
This herb is traditionally considered warming and drying in nature, with a bitter taste. It has a descending directionality and acts as a relaxing tonic predominantly on the qi aspect.
Primary Actions
- Laxative
- Choleretic
- Purgative
Indications
Western
- Chronic functional constipation
- Sluggish bowel movements
Syndromes
- Atonic constipation
- Biliary insufficiency
TCM
No established traditional indications.
Ayurveda
No established traditional indications.
Unani
No established traditional indications.
Constituents & Mechanisms
The bark contains anthraquinone glycosides such as rhein and emodin, which are responsible for its stimulant laxative effects. These phytochemicals increase intestinal motility and stimulate bile secretion.
Dosage & Preparations
- Tincture 1:5 45% ethanol 2-4 mL once or twice daily
- Standardized extract 10-30 mg anthraquinones daily
- Powdered bark 0.3-1 g infusion or decoction daily
- Cascara bark preparations as per pharmacopoeial guidance
Safety & Contraindications
Use only short term (7–10 days) to avoid dependence and electrolyte imbalance. Avoid use during pregnancy and lactation. Contraindicated in intestinal obstruction, inflammatory bowel disease, and abdominal pain of unknown cause. Possible interactions with diuretics, digoxin, and corticosteroids due to potassium loss risk.
Astrological Correspondences
No reliably sourced planetary or elemental rulers identified for this herb.
Selected References
- Herbal Medicine: Biomolecular and Clinical Aspects, 2nd Edition
- PFAF (Plants For A Future) Database – Rhamnus purshiana
- Commission E Monograph – Cascara bark
- The Desktop Guide to Herbal Medicine by P. Bradley