Rhamni purshianae cortex

Cascara is the common name for the bark of the plant Rhamnus purshiana DC.

The HMPC conclusions only cover cascara preparations that are obtained by drying and comminuting (reducing into tiny pieces) the bark. The dried, comminuted bark may also be put in a solvent (such as water or ethanol) to dissolve compounds and form a liquid extract. The solvent is then sometimes evaporated to obtain a dry extract. Cascara preparations are standardised to contain a defined amount of anthraquinones, which are substances linked with the activity of cascara.

Herbal medicines containing these cascara preparations are usually available as a herbal tea to be drunk, and in solid or liquid forms to be taken by mouth.

Cascara preparations may also be found in combination with other herbal substances in some herbal medicines. These combinations are not covered in this summary.

The HMPC concluded that these cascara preparations can be used for the short-term treatment of occasional constipation.

Cascara medicines should only be used in adults and adolescents over the age of 12 years and should not be taken for more than one week. Usually it is sufficient to take cascara medicines two to three times a week. If constipation continues or worsens while taking the medicine, a doctor or pharmacist should be consulted. Patients taking certain medicines should consult a doctor before taking cascara preparations at the same time.

Detailed instructions on how to take cascara medicines and who can use them can be found in the package leaflet that comes with the medicine.

Cascara medicines contain substances called anthraquinones, comparable to those found in other herbal laxatives such as senna. They stimulate bowel movements, encouraging the bowels to empty. They also alter the absorption of water and salt from the bowels. This increases the amount of water in the material in the gut and so softens it and allows it to pass along the gut more easily.

The HMPC conclusions on the use of these cascara preparations for occasional constipation are based on their ‘well-established use’ in this condition. This means that there are bibliographic data providing scientific evidence of their effectiveness and safety when used in this way, covering a period of at least 10 years in the EU.

There are no studies evaluating cascara alone or in combination with other laxatives. Therefore, the HMPC’s conclusions on the effects of cascara to treat constipation are based on extensive clinical experience and data on how the medicine works, as well as studies with other anthraquinone-containing substances.

For detailed information on the studies assessed by the HMPC, see the HMPC assessment report.

Side effects with cascara medicines include allergic reactions (such as itching and rash), abdominal (belly) pain, spasm and diarrhoea. Long-term use can lead to reactions including abnormal colouration of the bowel lining, which usually returns to normal when the patient stops taking the medicine, imbalance of water and salt in the body, presence of proteins and blood in the urine and yellow or red-brown colouration of the urine. The frequency of these side effects is not known.

Cascara medicines must not be taken by patients with obstructions or stenosis (narrowing) of the bowel, intestinal atony (loss of strength or movement in bowel muscles), appendicitis, inflammatory bowel diseases (such as Crohn's disease or ulcerative colitis), unexplained abdominal pain or severe dehydration. They must also not be taken during pregnancy, when breastfeeding or by children under 12 years of age.

Long-term use of laxatives like cascara should be avoided, as use for more than a short time may lead to the bowels not working properly and can cause dependence on laxatives.

Further information on the risks associated with cascara medicines, including the appropriate precautions for their safe use, can be found in the monograph which is published on the Agency’s website under the section ‘Documents’

Any applications for the licensing of medicines containing cascara have to be submitted to the national authorities responsible for medicinal products, which will assess the application for the herbal medicine and take into account the scientific conclusions of the HMPC. 

Information on the use and licensing of cascara medicines in EU Member States should be obtained from the relevant national authorities.

Further information on the HMPC assessment of cascara medicines, including details of the Committee’s conclusions, can be found in the section ‘Documents’.

For more information about treatment with cascara medicines, read the package leaflet that comes with the medicine or contact your doctor or pharmacist.