# Plant Monograph: Cascara Sagrada
**Name of plant:**
Cascara sagrada
**Catch phrase (Carmina Gadelica or traditional invocation if available):**
**“Sacred bark, open the way and restore the natural course.”**
No Carmina Gadelica invocation is associated with cascara sagrada. The name itself means **“sacred bark”** in Spanish and reflects the reverence with which the bark was regarded in some traditions. Cascara is native to western North America and should not be confused with European buckthorn (*Rhamnus cathartica*).
**Family:**
Rhamnaceae
**Genus and species:**
*Frangula purshiana* (DC.) A.Gray ex J.G.Cooper
(syn. *Rhamnus purshiana* DC.)
**Other names:**
* Cascara sagrada
* Cascara
* Sacred bark
* Chittem bark
* Pursh's buckthorn
* Cascara buckthorn
* California buckthorn
* Chittam bark
* *Frangula purshiana*
* *Rhamnus purshiana*
**Brief introduction:**
Cascara sagrada is a deciduous shrub or small tree native to the Pacific Northwest of North America. It is characterized by smooth grey-brown bark, glossy leaves and dark berries.
The dried bark has a long history of use as a **stimulant laxative**. Indigenous peoples of the Pacific Northwest used the plant for various medicinal purposes, and nineteenth-century North American herbal medicine adopted cascara as a relatively predictable laxative. The bark became an official pharmaceutical ingredient in the United States and Europe.
Fresh cascara bark is strongly irritating and can produce severe gastrointestinal effects. Traditionally, harvested bark was **aged for at least a year** or subjected to controlled drying before medicinal use.
**Traditional uses:**
* Used as a stimulant laxative for constipation.
* Used traditionally to relieve sluggish bowel function.
* Used historically as a bitter digestive tonic.
* Used in traditional North American medicine for various digestive complaints.
* Bark preparations were historically employed as a general “cleansing” remedy.
**Historical use:**
* Indigenous peoples of the Pacific Northwest used cascara bark medicinally, although traditional applications varied among nations.
* European-descended herbalists adopted the bark as a stimulant laxative during the nineteenth century.
* Cascara became an official drug in several pharmacopoeias.
* Pharmaceutical preparations were developed as standardized laxatives.
* Cascara was historically included in patent medicines and commercial digestive/laxative preparations.
**Parts used and method of use:**
* Aged dried bark.
* Bark extracts containing hydroxyanthracene derivatives.
Used as:
* Dried bark decoction or infusion in historical practice.
* Powdered aged bark.
* Fluid extracts and tinctures.
* Standardized oral stimulant-laxative preparations.
**Use in healing (modern herbal practice):**
* Short-term relief of occasional constipation.
* Stimulant laxative when other measures are inadequate.
* Historically used to promote bowel evacuation before the development of modern laxative medicines.
* Occasionally included in traditional “detoxifying” or bowel-cleansing formulas, although such prolonged use is not recommended.
* Modern use is generally limited to short-term constipation because safer alternatives are available.
Cascara is **not appropriate as a general daily digestive tonic or long-term cleansing herb**.
**Pharmacology and biochemistry:**
* **Cascarosides A–D** — major anthraquinone glycosides responsible for laxative activity.
* **Aloe-emodin and related anthraquinones** — active metabolites and related constituents.
* **Emodin and other hydroxyanthracene derivatives** — contribute to stimulant-laxative activity.
Mechanisms:
* Intestinal bacteria metabolize cascarosides into active anthrone derivatives.
* These metabolites stimulate the colonic mucosa and increase intestinal motility.
* They reduce absorption and increase secretion of water and electrolytes into the colon, producing softer stools and bowel evacuation.
**Overall profile:**
Cascara sagrada is a **potent stimulant laxative whose activity is well established pharmacologically**. Its hydroxyanthracene glycosides increase colonic motility and fluid secretion. It is appropriate only for **short-term occasional constipation**, not chronic bowel regulation or “detoxification.” Prolonged or excessive use can produce electrolyte disturbances, dehydration and dependence on stimulant laxatives.
**Common dosage:**
* **Aged dried bark:** approximately 0.3–1 g as a traditional laxative preparation.
* **Powdered aged bark:** approximately 0.3–1 g, depending upon anthraquinone content.
* **Standardized extract:** dosage sufficient to provide approximately **20–30 mg hydroxyanthracone derivatives calculated as cascaroside B**, according to historical pharmacopoeial standards.
* **Commercial stimulant-laxative preparation:** use only according to the product's standardized directions.
**Important:** Cascara preparations vary greatly in active constituent concentration. Modern dosing should therefore be based on **standardized preparations**, not simply grams of raw bark.
**Safety factors (including side effects):**
* Use only **properly aged and processed bark**; fresh bark may cause severe nausea, vomiting and intestinal irritation.
* Common adverse effects include abdominal cramping, diarrhea and electrolyte loss.
* Contraindicated in intestinal obstruction, undiagnosed abdominal pain, inflammatory bowel disease and other acute gastrointestinal conditions.
* Prolonged use can cause dehydration, hypokalemia, weakness and disturbances of normal bowel function.
* Long-term or excessive use of stimulant anthraquinone laxatives is not recommended; chronic use may cause dependence and structural/functional changes in the colon.
**First aid / adverse reaction response:**
* **Abdominal cramping or diarrhea:** discontinue use and replace fluids and electrolytes as appropriate.
* **Persistent or severe diarrhea:** seek medical attention, particularly if weakness, dizziness or dehydration develops.
* **Severe abdominal pain, vomiting or inability to pass stool/gas:** seek urgent medical assessment because intestinal obstruction or another acute condition must be excluded.
* **Symptoms of electrolyte disturbance** such as marked weakness, muscle cramps, palpitations or confusion: discontinue use and seek medical attention promptly.
* **Severe dehydration, fainting or collapse:** seek emergency medical attention.
**Drug interactions:**
* May increase potassium loss when used with **diuretics**, increasing the risk of hypokalemia.
* May interact with **cardiac glycosides/digoxin**, because low potassium can increase susceptibility to cardiac glycoside toxicity.
* May reduce potassium levels when combined with **corticosteroids** or other medicines that promote potassium loss.
* May reduce absorption or alter the effect of other orally administered medicines when severe diarrhea occurs; stimulant laxatives should not be combined casually with other laxatives.
**Horticultural requirements:**
* **USDA / Canadian zone:** Approximately USDA zones 5–9.
* **Soil pH:** Approximately 5.0–7.0; prefers slightly acidic to neutral soils.
* **Light requirements:** Full sun to partial shade.
* **Moisture:** Moist, well-drained soil; naturally associated with moist woodland environments.
**Other notes (growth habit, harvest timing, etc.):**
* **Growth habit:** Deciduous shrub or small tree, commonly 5–15 m tall, sometimes larger under favourable conditions.
* **Flowering/fruiting:** Small greenish flowers appear in late spring, followed by berry-like fruits that mature from green to red and finally dark purple-black.
* **Harvest timing:** Medicinal bark is harvested from mature branches and historically aged for at least a year before use. Commercial preparations use controlled drying and processing.
* **Habitat:** Moist forests, woodland margins and riparian environments of western North America, particularly from British Columbia through the Pacific Northwest and northern California.
* **Propagation/cultivation notes:** Propagated primarily by seed. Prefers fertile, moist soil and woodland-like conditions. Seeds may require stratification for reliable germination.
**Sampling of clinical reports / studies:**
* **Clinical evidence:** Hydroxyanthracene-containing laxatives have well-established short-term efficacy for occasional constipation, although modern clinical practice generally favours better-characterized alternatives.
* **Pharmacological study:** Cascarosides are metabolized by intestinal bacteria into active anthrone derivatives that stimulate colonic motility and increase intestinal water secretion.
* **Phytochemical study:** The bark contains cascarosides, aloe-emodin, emodin and related hydroxyanthracene derivatives; aging alters the chemical profile and reduces the harshness of fresh bark.
* **Ethnobotanical evidence:** Indigenous peoples of the Pacific Northwest used cascara for a variety of traditional purposes, while nineteenth-century European-American medicine adopted it primarily as a laxative.
* **Overall assessment of evidence:** **Strong pharmacological and historical evidence for short-term stimulant-laxative activity; limited role in modern herbal medicine because of safety concerns and availability of better-characterized laxatives. Cascara should not be used chronically or as a routine “detox” herb.**
Educational Use Only: The information presented on this page is provided for educational, historical, and informational purposes only. ArdNemeton na Tuatha and Bhùth Draoi do not provide medical advice. Always consult your physician and pharmacist before using any herb, mushroom, supplement, or botanical product for medicinal purposes. Traditional uses described herein do not constitute medical claims.