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Evidence-Based Complementary and Alternative Medicine
Volume 2014, Article ID 879396, 8 pages
Review Article

Valerian: No Evidence for Clinically Relevant Interactions

1Working Group Efficacy, Safety and Interactions of Kooperation Phytopharmaka GbR, Plittersdorfer Straße 218, 53173 Bonn, Germany
2Medical Information and Clinical Research, Steigerwald Arzneimittelwerk GmbH, 64295 Darmstadt, Germany
3Institute of Pharmacy, University of Leipzig, 04103 Leipzig, Germany
4Center of Internal Medicine, Universitätsmedizin Rostock, 18057 Rostock, Germany

Received 8 January 2014; Revised 23 March 2014; Accepted 12 May 2014; Published 30 June 2014

Academic Editor: Igho J. Onakpoya

Copyright © 2014 Olaf Kelber et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


In recent popular publications as well as in widely used information websites directed to cancer patients, valerian is claimed to have a potential of adverse interactions with anticancer drugs. This questions its use as a safe replacement for, for example, benzodiazepines. A review on the interaction potential of preparations from valerian root (Valeriana officinalis L. root) was therefore conducted. A data base search and search in a clinical drug interaction data base were conducted. Thereafter, a systematic assessment of publications was performed. Seven in vitro studies on six CYP 450 isoenzymes, on p-glycoprotein, and on two UGT isoenzymes were identified. However, the methodological assessment of these studies did not support their suitability for the prediction of clinically relevant interactions. In addition, clinical studies on various valerian preparations did not reveal any relevant interaction potential concerning CYP 1A2, 2D6, 2E1, and 3A4. Available animal and human pharmacodynamic studies did not verify any interaction potential. The interaction potential of valerian preparations therefore seems to be low and thereby without clinical relevance. We conclude that there is no specific evidence questioning their safety, also in cancer patients.