Valerian, St John’s Wort, Echinacea, and Ginkgo are the main OTC herbal medicinal products available in pharmacies. They are usually requested specifically by people walking into the pharmacy. But they can also be safely recommended. Pharmacist tend not to recommend herbal products due to various reasons, namely due to lack of understanding, and concerns about efficacy and safety. However, in the UK we need to appreciate the benefits of herbal medicinal products as they do in mainland Europe. To do that the pharmacist need to understand a few points about herbal medicinal products.

If someone walks into your pharmacy complaining of insomnia but does not want the “hangover” effect of old antihistamines, then valerian can be recommended. The main concern for a pharmacist here should be safety. New legislations are in place to ensure all herbal medicinal products being sold are licensed, and these products carry a THR number, which is analogous to the PL number of regular medicines. This number indicates that the product is safe to use for a particular indication, dose reproducibility acceptable according to the MHRA, and the product comes with a Patient Information Leaflet. Therefore, recommending licensed valerian tablets is a good call! THR ensures safety, but does it guarantee efficacy? NO. Unlike medicines that carry a PL number, THR medicines do not need to go through clinical trials. Their efficacy is based on decades of traditional use. This can be roughly translated into [this medicine may help you with your symptoms, but it won’t poison you if you use it correctly!].

Another important concept in herbal medicinal products is standardisation. Usually a chemical compound (or compounds) from a plant are used to determine the quality of the product. A tablet of senna usually contains 7.5mg of sennosides. Here, sennosides are the quality marker compound and also the active principal. Therefore, every senna tablet should contain that amount of sennosides. Similarly, St John’s Wort is standardised using hypericin.

Interactions and contraindications are common when herbal medicinal products are used, some are severe. The main culprits are St John’s Wort and ginkgo. The former can significantly induce hepatic CYP450 enzymes reducing the plasma levels of many drugs, ultimately reducing their effect.  For example St John’s Wort must not be given to women on contraceptives. Ginkgo has an anticoagulant effect and should not be recommended for anyone with a coagulation disorder like haemophilia, or anyone taking anticoagulants like warfarin or heparins. Some individuals may have an allergic reaction to daisy plants, and a similar reaction can occur if they take Echinacea. This is because both plants belong to the Asteraceae family.


  • Recommend herbal medicinal products after establishing safety and quality.
  • Establish safety and quality by looking for THR number on the product and looking at the standardisation information.
  • Efficacy is only based on traditional use (except for senna).
  •  Just because it comes from a plant, does not mean it is safe for everyone.
  • Check for interactions and contraindications.

Mohamed Abdelrahman

Pre-Registration Pharmacist