Ricini oleum

Castor oil is the common name for the oil obtained from the seeds of the plant Ricinus communis L.

The HMPC conclusions only cover castor oil preparations which are obtained by 'cold expression' of the seeds. This means that the oil is extracted from the seeds by crushing and pressing them without heating.

Herbal medicines containing these castor oil preparations are usually available in solid or liquid forms to be taken by mouth.

Castor oil 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 castor oil preparations can be used for short term as laxatives for occasional constipation.

Castor oil medicines should only be used in adults, and should not be taken for longer than one week without medical supervision. Detailed instructions on how to take castor oil medicines and who can use them can be found in the package leaflet that comes with the medicine.

When ingested, castor oil is broken down into ricinoleic acid which works by reducing absorption of fluid and salts in the small intestine (the upper part of the bowel). This increases the water content of stools, making them softer and easier to pass. In addition, castor oil stimulates movement in the intestines which will help to pass the stools.

The HMPC conclusions on the use of these castor oil medicines as laxatives 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, the HMPC considered two clinical studies which showed a laxative effect for castor oil medicines in constipated patients. In one of the studies the effects of castor oil capsules were similar to those of senna capsules (another herbal preparation commonly used to treat constipation).

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

Side effects have been reported with castor oil. These include nausea, vomiting abdominal (belly) pain and severe diarrhoea.

Castor oil medicines should not be taken in case of obstruction or narrowing of the gut, atony (loss of normal movement in the gut muscle), appendicitis (inflammation of the appendix, a small organ connected to the bowel), inflammatory diseases of the colon (the lower part of the bowel), unexplained abdominal pain and severe dehydration. They should not be used during pregnancy and breastfeeding.

Further information on the risks associated with castor oil medicines, including the appropriate precautions for their safe use, can be found in the monograph under the tab 'All documents'.

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

Further information on the HMPC assessment of castor oil medicines, including details of the Committee's conclusions, can be found under the tab 'All documents'.

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