Polygoni avicularis herba

Knotgrass herb is the common name for the flowering aerial parts of the plant Polygonum aviculare L.

The HMPC conclusions only cover knotgrass herb preparations which are obtained by drying and comminuting (reducing into tiny pieces) the flowering aerial parts.

Herbal medicines containing these knotgrass herb preparations are usually available as herbal material that is used to make herbal teas to be drunk or added to water to produce a liquid (decoction) to be applied to the lining of the mouth.

Knotgrass herb 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 on the basis of its long-standing use, these knotgrass herb preparations can be used for the relief of symptoms of common cold, for treating symptoms of minor mouth or throat inflammation and for minor problems affecting the urinary tract (structures that carry urine) to increase the production of urine in order to achieve flushing of the urinary tract.

Knotgrass herb medicines should only be used in adults and adolescents over the age of 12 years. If symptoms last longer than one week or worsen during the use of the medicine for common cold symptoms or for minor mouth or throat inflammation, a doctor or qualified healthcare practitioner should be consulted. If symptoms last longer than two weeks or worsen during the use of the medicine for minor urinary tract problems a doctor or qualified healthcare practitioner should be consulted. Detailed instructions on how to take knotgrass herb medicines and who can use them can be found in the package leaflet that comes with the medicine.

The HMPC conclusions on the use of these knotgrass herb medicines for common colds, minor mouth or throat inflammation and minor problems affecting the urinary tract are based on their 'traditional use'. This means that, although there is insufficient evidence from clinical trials, the effectiveness of these herbal medicines is plausible and there is evidence that they have been used safely in this way for at least 30 years (including at least 15 years within the EU). Moreover, the intended use does not require medical supervision.

In its assessment, the HMPC considered a clinical study in men with gingivitis (inflammation of the gum). Although a possible effect in decreasing gingivitis was observed, information on how the study was conducted is incomplete, so firm conclusions could not be drawn. The HMPC also considered studies in laboratory tests which support anti-inflammatory and antibacterial effects of knotgrass herb medicines. However, because of the limitations with the available data, the HMPC conclusions on the use of these knotgrass herb medicines are based on their long-standing use.

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

At the time of the HMPC assessment, no side effects had been reported with these medicines.

Further information on the risks associated with knotgrass herb 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 knotgrass herb 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 knotgrass herb medicines in EU Member States should be obtained from the relevant national authorities.

Further information on the HMPC assessment of knotgrass herb medicines, including details of the Committee's conclusions can be found under the tab 'All documents'. For more information about treatment with knotgrass herb medicines, read the package leaflet that comes with the medicine or contact your doctor or pharmacist.