Botanical characteristics

• Size: A small tree or large shrub, cascara typically grows 15 to 30 feet tall.
• Leaves: The leaves are oval-shaped with prominent veins, dark green on top, and paler underneath. In the fall, they turn yellow, orange, or red.
• Flowers: The tree produces small, inconspicuous, greenish-white flowers in the spring that attract butterflies.
• Fruit: The flowers are followed by small, bead-like berries that are first red and then ripen to a deep purple or black color. The fruit is a food source for many native birds.
• Bark: The bark is smooth and mottled grey, resembling red alder.
• Habitat: Cascara is native to the Pacific Northwest, with a range stretching from British Columbia to California and inland to western Montana. It is adaptable to a variety of conditions, from dry to wet soil and sun to shade, but thrives best in partial sun with well-drained soil. 

Medicinal uses and precautions

The bark of Rhamnus purshiana contains anthraquinone compounds called cascarosides, which stimulate the bowel and act as a laxative. 

• Aging is essential: Fresh cascara bark contains powerful chemicals that can cause severe gastrointestinal distress, including intestinal spasms and vomiting. The bark must be dried and aged for at least one year to allow these chemicals to degrade into the gentler laxative compounds.
• Safety and side effects:
  • Short-term use: The aged bark is safe for short-term use (up to one or two weeks) to treat constipation. Side effects can include abdominal cramps and discomfort.
  • Long-term use: Prolonged use can lead to dehydration, electrolyte imbalances (especially low potassium levels), and loss of normal bowel function.
  • Not for everyone: Cascara is not recommended for pregnant or breastfeeding women, children, or individuals with intestinal obstructions, Crohn's disease, or ulcerative colitis. 

History and modern regulations

• Traditional use: Native American tribes in the Pacific Northwest used the dried cascara bark for centuries as a laxative and for other ceremonial purposes.
• Over-the-counter status: In 2002, the U.S. Food and Drug Administration (FDA) banned cascara as an over-the-counter (OTC) laxative ingredient due to manufacturers' failure to provide evidence of its safety and efficacy.
• Dietary supplement: While no longer approved for OTC laxatives, cascara is still legally sold as a dietary supplement.