Cascara Sagrada Summary:

Cascara sagrada, otherwise known as buckthorn, comes from the genus Rhamnus. This genus actually has a few species that are used in the same way. The main ones being Rhamnus purshiana, and Rhamnus frangula. The bark of this tree is mainly used as a laxative, and bowel tonic. The fresh bark is rarely used, as it tends to be very powerful and may cause side effects like griping (spasmodic intestinal pain), and vomitting.

Once the bark has been aged around 3 years it's significantly milder, and much more useful medicinally. The taste of the bark is incredibly bitter and hard to palate, which is why this herb is mainly found as an extract in capsule form these days. Cascara sagrada can also be found in a liquid extract form. People who wish to maximize the benefits of the bitter components of this herb often choose to go with the liquid extract version. 

Cascara sagrada stimulates digestion through its bitter components, and through an activation of the bitter receptors on the tongue and throughout the digestive tracts. It also exerts a mild laxative action on the upper instestines. Due to its mild nature, it can be used in the elderly, and in chronic constipation conditions (unlike many of the other laxative botanicals). 

Botanical Name

Rhamnus purshiana
Frangula purshiana



Part Used


Herbal Actions:

  • Stimulating laxative
  • Cholagogue
  • Bitter digestive stimulant
  • Antiparasitic
  • Mild Laxative
  • Stomachic
  • Appetite stimulant
rhamnus spp bark.jpeg


Liquid Extract (1:2)

3-8 mL/day

Find It Here

+ Indications

  • Constipation (Acute and chronic)
  • Flatulence
  • Bloating
  • Abdominal fullness
  • Postprandial bloating
  • Dyspepsia
  • Weak gastric secretion
  • Anorexia
  • Itching skin
  • Headache (Due to constipation or intestinal weakness)
  • Haemorrhoids
  • Itching skin

+ Contraindications

  • Pregnancy or lactation
  • Intestinal obstruction
  • Intestinal inflammations (Crohn's disease, ulcerative colitis, appendicitis)
  • Children under the age of 12
  • Not appropriate for long term use

Common Names:

Cascara Sagrada

Sacred Bark


Californian Buckthorn

Rhamnus purshiana

Frangula purshiana


Traditional Uses:

Traditional use of cascara sagrada included: intestinal tonic, dyspepsia, constipation, digestion related headaches, to loosen stool for conditions such as haemorrhoids, rheumatism, biliary catarrh with jaundice, and chronic liver diseases [6]. 

Native Americans used cascara sagrada as a cathartic [6]. 


    Botanical Description

    Cascara sagrada is a small tree, with 8-13 cm long leaves. 


    Habitat Ecology, and Distribution

    Cascara sagrada can be found growing around the rocky mountains of western Canada and the United States. 


    Harvesting Collection, and Preparation

    The bark of cascara sagrada is harvested in spring and early summer. During this time it is easily peeled from the tree. It is then dried in the shade. Aged bark (3 years) is generally the preferred product, as the emetic effects lessen over this time and is much less likely to cause issues with griping and emesis [5].



    Chemical class Chemical Name % Dried Weight Solubility
    Anthrone glycosides Cascarosides Unknown N/A
    Anthraquinones Aloe-emodin, Emodin, Chrysophanol Unknown N/A
    Aloins --- Unknown N/A
    Deoxyaloins --- Unknown N/A
    Tannins --- Unknown N/A
    Volatile Oils --- Unknown N/A

    Pharmacology and Medical Research:

    + Anticancer

    The anthraquinone emodin, contained within cascara sagrada and other herbs in its family (Rhamnaceae) as well as the families Lilliaceae, and Leguminoseae, is an important medicinal constituent. It is similar in structure to anthracycline, which is a class of chemicals used in cancer chemotherapy. They work to intercalate the DNA of cancer cells. Similar antitumor antibiotics includes daunorubicin and mitoxantrone. [7]. Emodin possesses many of these effects as well, with documented anti-proliferative [1-3], anti-angiogenic [8, 9], and radio-sensitizing/chemotherapy sensitizing actions on cancer cells [10-12]. It has even been found to reverse multidrug-resistant cancer cells [13].

    Emodin has been shown to have a broad spectrum inhibitory action on such cancer cell lines as leukemia [14, 15], lung cancer [16-18], hepatic cancer [27-29], gallbladder cancer [21-23], pancreatic cancer [24-26], breast cancer [30-32], colon cancer [19, 20], and cervical cancer [33]. Most of this research has been conducted in China, and it should be noted that this chemical is contained within some of the most important and widely used traditional Chinese herbal medicines including Chinese rhubarb (Rheum palmatum) [34].

    The anticancer actions of emodin, has been suggested to be due to a variety of mechanisms such as the casein kinase Ⅱ and ERK1/2 pathways [7].

    The bioavailability of this chemical is quite low however, and has some toxicity in vivo as well [7]. It may however prove useful in combination, as in the case of many Chinese formulas containing emodin containing botanicals, or may prove useful administered via intravenous, or through modification of one of it's side chains [7]. It was shown in fact, that with the addition of polymethyleneamine, sugar or heterocycle as side chains may actually improve the antitumor activity [35-37]. Rhamnus frangula has been found to have emodin-glycoside derrivatives [38], some of which fit the earlier hypothesis, showing that these emodin glycoside derivatives (emodin with the addition of sugar chains) have a significantly higher antitumor activity than emodin, and have an improved bioavailability as well [39-41].

    The emodin glycoside derivative EM-d-Rha for example has shown a 10 fold improvement in anti-proliferative activity and growth inhibition of cancer cells (HepG2 cells and OVCAR-3 cells). The mechanism of action for this chemical was suggested to be through induction of apoptosis via the intrinsic apoptotic signal pathway (release of apoptosis-inducing factors and Cytochrome C from mitochondria, followed by the activation of caspase-3) [7].

    + Antiviral

    In an older study (1991) anthraquinones extracted from cascara sagrada were found to inhibit enveloped viruses from adsorption into a cell through an interaction with the viral envelope. Thus it was able to prevent its subsequent replication. [4].

    + Laxative

    The laxative actions of cascara sagrada are reported to be from the hydroxyanthracene derivatives. They travel through the digestive tract unabsorbed to the large intestine where they are metabolized to form active aglycones. Here they exert laxative effects by a localized modification of intestinal motility via stimulation of intestinal muscle, and an accumulation of fluid. This occurs due to mediators such as prostaglandin release, and nitric oxide synthase production. [6].



    • Pregnancy and lactation (only very small doses acceptable) [6]
    • Intestinal obstruction [6]
    • Intestinal inflammations such as: [6]
    • Chrons disease
    • Ulcerative colitis
    • Appendicitis
  • Not for use in children under 12 [6] 


    • May cause bowel pigmentation
    • Do not use over 2 weeks without medical supervision [6]
    • Do not use fresh cascara sagrada. Severe vomiting, and intestinal spasm may ocurr [6]. 


    • 1 pt cascara, 2 pts chamomile, 4 pts psyllium combination to tone the bowels and improve function. Safe to use in this ratio over many weeks. Take 1 time/day before meals
    • Suggested synergy with boldo for digestive complaints such as constipation, flatulence, and abdominal fullness [6]. 
    • Combine with rhubarb, boldo, and gentian for dyspepsia [6]. 

    Other Uses:

    Cascara sagrada can be used effectively as a mild purgative for dogs with chronic constipation. This is especially useful if the tone of the bowels is weak and needs improvement as is common with chronically constipated dogs [5]. 


    Justin Cooke

    The Sunlight Experiment

    Updated: June 2017

    Recent Blog Posts:


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