Rhei radix

Rhubarb root is the common name for the root of either of two species of rhubarb plant, known in Latin as Rheum palmatum L. and Rheum officinale Baillon, or their hybrids.

The HMPC conclusions only cover rhubarb root preparations that are obtained by drying and comminuting (reducing into tiny pieces) the root. The dried, comminuted root may also be put in a solvent to dissolve compounds and obtain an extract. Rhubarb root preparations are standardised to contain a defined amount of anthraquinones, which are substances linked with the activity of the medicine.

Herbal medicines containing these rhubarb root preparations are usually available as herbal tea to be drunk and in liquid and solid forms to be taken by mouth.

Rhubarb root 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 rhubarb root preparations can be used for the short-term treatment of occasional constipation

Rhubarb root medicines should only be used in patients over the age of 12 years and should not be taken for more than a week. Usually it is sufficient to take them two to three times a week. If constipation continues or worsens while taking the medicine, a doctor or pharmacist should be consulted. Detailed instructions on how to take rhubarb root medicines and who can use them can be found in the package leaflet that comes with the medicine.

Rhubarb root contains 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 rhubarb root medicines for constipation are based on their ‘well-established use’. 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.

In its assessment, as well as the long clinical experience with the use of rhubarb root preparations the HMPC considered studies showing the stimulant effect of anthraquinones on bowel muscles.

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

Side effects with rhubarb root medicines include allergic reactions (such as itching or rash), stomach pain and cramping (sometimes as a result of too high a dose), and diarrhoea. Long-term use can lead to reactions including abnormal colouring of the bowel lining, which usually returns to normal when the patient stops taking the medicine, imbalance of salts and water in the body, passage of protein or blood in the urine and yellow or brown coloration of the urine The frequency of these side effects is not known.

Rhubarb root medicines must not be used in patients with obstructions or stenosis (narrowing) of the bowel, intestinal atony (loss of strength or movement in bowel muscles), appendicitis, inflammatory bowel disease such as Crohn’s disease or ulcerative colitis, unexplained abdominal (belly) 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 rhubarb root 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 these rhubarb root medicines, including the appropriate precautions for their safe use, can be found in the monograph under the section 'Documents'.

Any applications for the licensing of medicines containing rhubarb root 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 rhubarb root medicines in EU Member States should be obtained from the relevant national authorities.

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

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