Cascara sagrada is a tree that grows natively along the Pacific Coast of North America and is used medicinally for its bark. From the species Rhamnus purshiana, cascara is most often used for its laxative effects. You should talk with your doctor before taking cascara sagrada, because the herbal remedy poses some potentially serious side effects and risks.
Native Americans in Northern California began using cascara and introduced the remedy to explorers from Spain during the 1500s, says the University of Michigan Health System. The Native Americans called cascara "sacred bark" and used it as a laxative to treat constipation. They dried and aged the bark, because taking fresh cascara caused extreme vomiting, Drug Digest notes.
Mainly, you can use cascara to treat constipation, due to its laxative effects (references 1, 2 & 3). Cascara sagrada may also help to support cancer treatment, either by enhancing chemotherapy or by the herb's own anticancer actions, says the Memorial Sloan-Kettering Cancer Center. You can take capsules of dried cascara sagrada that equate to 20 to 30 mg of cascarosides per day, or you can take ¼- to 1 teaspoon of cascara extract tincture per day. Drink plenty of water while using cascara and don't take the herb for longer than eight to 10 consecutive days, the University of Michigan advises.
Cascara contains anthraquinones that stimulate the intestines to contract and preserve water in the bowels, softening the stools, says drugdigest.com. These hydroxyanthraquinone glycosides, known as cascarosides, are responsible for the stimulant laxative effects of cascara sagrada. Cascara's other active components--emodin and aloe-emodin--may offer chemotherapy-enhancing and cancer-fighting effects, says Memorial Sloan-Kettering Cancer Center. Emodin also stimulates the circular smooth muscles in the colon to induce stool passage.
Cascara's stimulant laxative effects are well-studied and confirmed. Clinical trials and studies on the herb's efficacy for treating constipation have been published in "The Healing Herbs" in 1991, the "Encyclopedia of Common Natural Ingredients Used in Food, Drugs, and Cosmetics" in 1996, and several other medical journals and publications. The U.S. Pharmacopoeia approved the use of cascara in treating constipation in 1890. Additionally, cascara sagrada has been studied for its anticancer actions. A 2002 study found that emodin isolated from cascara had anticancer effects on skin cancer cells in mice, and a 2007 test tube study found that emodin helped to inhibit human carcinoma cells.
Because cascara sagrada is a stimulant laxative, it may cause diarrhea that can lead to dehydration and potassium loss. Low potassium levels in your body can cause heart problems. Never take cascara that hasn't been aged and dried for at least one year, because taking fresh cascara can cause severe vomiting and cramps. Don't take cascara sagrada if you have gastrointestinal or abdominal problems such as Crohn's disease, appendicitis or intestinal obstructions, because the herb may worsen your condition. Also, don't take cascara while you're taking corticosteroids, diuretics, or "water pills," digoxin or other laxatives. Avoid giving cascara to children younger than 12 years old, and don't take the herb if you're pregnant or breastfeeding, because cascara can enter the breast milk and cause diarrhea in the nursing infant. Beware that in 2002, the U.S. Food and Drug Administration ruled that cascara sagrada wasn't safe for use as a stimulant laxative in prescription or over-the-counter medications, but you may still find cascara in dietary supplements.