Herbal and homeopathic medicines: reminder to be vigilant for suspected adverse reactions and to report them to the Yellow Card scheme

If an adverse drug reaction is suspected, ask patients if they are taking any herbal or homeopathic medicines and report any suspicions to the Yellow Card scheme. Remind patients to check that a herbal or homeopathic medicine is licensed and to follow the advice included in the patient information.

Advice for healthcare professionals:

  • be vigilant for suspected adverse reactions associated with the use of herbal and homeopathic medicines and interactions with other medicines and report suspicions to the MHRA’s Yellow Card scheme (see section below for what to include in reports)
  • if an adverse reaction is suspected, ask patients whether they are taking any herbal or homeopathic medicines and include a full list of medicines in the Yellow Card report
  • enquire if patients are taking herbal or homeopathic medicines during routine medicine reviews and remind them to check they are using licensed products (see advice to provide to patients below)
  • remind patients to read the safety information provided in the patient information for herbal and homeopathic medicines, including when to seek medical advice

Advice for healthcare professionals to provide to patients:

  • to ensure a product has been licensed by the MHRA and meets the required standards of quality, safety, and patient information:
    • check for the Traditional Herbal Registration (THR) Certification Mark and THR number on the label of traditional herbal medicines (some herbal medicines have a product licence, shown by a product licence (PL) number)
    • check for the Simplified Homeopathic Registration (HR) or National Rules Authorisation (NR) number on the label of homeopathic medicines
  • always read the patient information provided with a herbal or homeopathic medicine to ensure that it is suitable for you and that you know how to use it safely
  • if you suspect you have had an adverse reaction to a herbal or homeopathic medicine, you can report this to your doctor or pharmacist, or directly to the MHRA’s Yellow Card scheme

Yellow Card reporting for herbal and homeopathic medicines

The Yellow Card scheme is vital in helping the MHRA to monitor the safety of all medicines in the UK, including herbal and homeopathic medicines.

Herbal and homeopathic medicines are available from outlets such as pharmacies, retail stores, online shops or supplied by herbal or homeopathic practitioners and only some of these are licensed by the MHRA. Here we provide several examples of why it is important that we monitor both licensed and unlicensed herbal and homeopathic medicines in order to protect patient safety.

Yellow Card reporting has identified many important safety issues for herbal medicines, for example, interactions between St John’s wort and hormonal contraceptives and antiepileptic medicines, which were unknown before being reported.

In addition, our vigilance of herbal products has led to warnings regarding the use of Butterbur (Petasites hybridus) products. Butterbur contains pyrrolizidine alkaloids, which can cause serious adverse effects such as liver damage and organ failure. The MHRA has previously published a safety alert advising consumers not to take unlicensed Butterbur herbal remedies. This advice remains unchanged.

Although homeopathic medicines are sometimes diluted to contain only a few molecules of active ingredient, a recent study highlighted a manufacturing error for a homeopathic medicine that resulted in an accidental atropine overdose and hospitalisation of a patient in Germany.[footnote 1] Although this occurred outside of the UK, it is an example of the need to consider these medicines in patients who have an adverse reaction.

Who advises the MHRA on herbal and homeopathic medicines?

The independent Herbal Medicines Advisory Committee (HMAC) and Advisory Board on the Registration of Homeopathic products (ABRHP) advise the MHRA and Ministers on the safety, quality and patient information for traditional herbal and homeopathic medicines.

HMAC and ABRHP review safety issues identified for traditional herbal and homeopathic products via the reporting of Yellow Card reactions and advise on changes to the safety information for UK licensed products when required.

Knowing whether a herbal or homeopathic medicine is licensed in the UK

For herbal medicines, patients should check for:

For homeopathic medicines, patients should check for a:

  • A Simplified Homeopathic Registration (HR) number
  • Or a National Rules Authorisation (NR) number

Choosing a product that is licensed means that it meets the required standards of quality, safety, and patient information.

Report suspected adverse reactions to herbal or homeopathic medicines

A recent study of a cohort of people in Wales showed that fewer than 1 in 3 participants knew that they could report an adverse reaction to a herbal medicine or homeopathic medicine to the Yellow Card scheme.[footnote 2]

Healthcare professionals and patients are encouraged to report all suspected side effects or adverse reactions to any herbal or homeopathic medicine using the Yellow Card scheme.

When reporting a Yellow Card, it is good practice to routinely ask patients which other medicines, including herbal medicines, supplements, and homeopathic medicines they are taking, in addition to those they have bought themselves, and listing these in the report. You can also inform patients they can self-report any side effects directly using the Yellow Card app or website.

What to include when submitting a Yellow Card for herbal and homeopathic medicines

Use the Yellow Card website or Yellow Card app (download from the Apple App Store or Google Play Store) to report suspected reactions to herbal and homeopathic medicines.

When submitting a Yellow Card for herbal and homeopathic medicines, it is important to provide some extra details to help us with our assessment and to identify the exact herbal or homeopathic product, such as:

  • the brand name (if it has one)
  • the list of ingredients
  • details of the manufacturer or supplier and THR/PL/HR/NR number (if it has one)
  • the condition it was being used for
  • any other medicines taken in the previous 3 months
  • if the product was supplied by a herbal or homeopathic practitioner, their name and address
  • a photograph of package labelling (emailed to yellowcard@mhra.gov.uk)

If you do not have all the above information, please still complete a Yellow Card.

If the reaction is severe, you can also retain a sample of the product, in case further investigations are required. Please note that you can also report suspected reactions that arise as a result of error, misuse, abuse, or off-label use. If in doubt about whether to report a suspected reaction, please complete a Yellow Card.

Article citation: Drug Safety Update volume 14, issue 12: July 2021: 2.

  1. Schmoll S, Romanek K, and others. Anticholinergic syndrome after atropine overdose in a supposedly homeopathic solution: a case report. Clinical Toxicology. 2021. 1–3 

  2. Bracchi RC, Tseliou F, and others. Public awareness in Wales of the UK Yellow Card scheme for reporting suspected adverse drug reactions. British Journal of Clinical Pharmacology 2021; 1-5 

Published 7 July 2021