The Expert Committee on Specifications for Pharmaceutical Preparations gives recommendations and provides independent international standards and guidelines in the area of quality assurance for implementation by WHO Member States, international organizations, United Nations agencies, regional and interregional harmonization efforts, as well as WHO's medicine-related programs and initiatives. In this 43rd report, 25 new monographs for inclusion in "The International Pharmacopoeia" together with five new International Chemical Reference Substances (ICRS) were adopted. These monographs will allow the quality control testing of HIV/AIDS, TB and malaria medicines. They also include a series of new specifications for radiopharmaceuticals and medicines for children. In addition the newly revised WHO Stability testing of active pharmaceutical ingredients and finished pharmaceutical products, and the procedures for prequalification of pharmaceutical products, as well as for assessing the acceptability, in principle, of active pharmaceutical ingredients for use in pharmaceutical products were adopted and are published in this report.