WHO published Quality control methods for medicinal plant materials in 1998 inorder to support WHO Member States in establishing quality standards andspecifications for herbal materials, within the overall context of qualityassurance and control of herbal medicines. This is the updated edition of the1998 publication, with an updated title.

The purpose of this updated edition remains unchanged from that of the firstedition. It is to support the development of national standards based on localmarket conditions, with due regard to existing national legislation and nationaland regional norms. It describes a series of internationally harmonized testsfor assessing the quality of herbal materials, including the determination ofpesticide residues, arsenic and toxic heavy metals, microorganisms andaflatoxins.

A collection of recommended test procedures for assessing the identity, purity,and content of herbal materials, intended to assist national laboratoriesengaged in pharmaceutical quality control, the manual responds to the growinguse of herbal medicines, the special quality problems they pose, and thecorresponding need for international guidance on reliable methods for qualitycontrol. Where relevant, suitable test apparatuses are illustrated andexplained.

The publication includes chapters that cover internationally harmonizedprocedures for preparing culture media, strains of microorganisms suitable foruse in tests, specifications for adsorbents for use in thin-layerchromatography, and detailed descriptions of the reagents, test solutions, andvolumetric solutions used in the recommended tests.

Recommended procedures - whether involving visual inspection or the use ofthin-layer chromatography for the qualitative determination of impurities -should also prove useful to the pharmaceutical industry and pharmacists workingwith herbal materials.

In order to promote good practices and to provide general technical guidance inconducting the test methods described in this publication, WHO good practicesfor pharmaceutical quality control laboratories is annexed to this publicationfor easy reference. The scope of the good practice guidance includespharmaceutical laboratories handling herbal medicines, and an example of a listof equipment for pharmacognosy/phytochemical laboratories is provided therein.

This new edition will continue to serve as key technical training material fornational capacity-building in setting standards for herbal medicines. Thispublication is an example of the immediate response of WHO in the implementationof the resolution on Global strategy and plan of action on public health,innovation and intellectual property that was adopted by the Sixty-first WorldHealth Assembly in 2008.