WHO Health Systems Library
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WHO Guidelines for Assessing Quality of Herbal Medicines with Reference to Contaminants and Residues
(2007; 118 pages)


This WHO guidelines present general consideration on potentially hazardous contaminants and residues in herbal medicines and include guiding principles of assessing quality of herbal medicines, in terms of major contaminants and residues. It also recommends analytical methods for qualitative and quantitative determination of such contaminants and residues.

Within overall context of quality assurance, these guidelines intended to provide general technical guidance to Member States in assessing quality relating to safety of herbal materials and products classified as medicines, with regards to major and common contaminants and residues.

The objectives of these guidelines are to provide:

  • guiding principles for assessing the quality in relation to the safety of herbal medicines, with specific reference to contaminants and residues;
  • model criteria for use in identifying possible contaminants and residues;
  • examples of methods and techniques; and
  • examples of practical technical procedures for controlling the quality of finished herbal products.

The scope of these guidelines does not cover issues of adulteration of herbal medicines and/or counterfeit products.

The annexes to these guidelines present several examples of suitable methodologies found in national or regional pharmacopoeias and in WHO documents. It should be noted that these methods need to be validated for the material that is to be tested, and also for each type of instrument.

Last updated: May 4, 2012