As the global market for pharmaceuticals increases, the adverse consequences of different regulations and requirements are becoming more obvious. Discussions between the regulatory authorities for the European Community, United States and Japan under the International Conference on Harmonization (ICH) intended to remove some of these differences are mirrored by similar discussions between the corresponding pharmacopoeial authorities. Moves towards harmonized requirements in pharmacopoeial monographs depend on a consensus view of the purpose and scope of their contents. Aspects of the construction of the four main elements (identification, characterization, control of impurities and assay) of a monograph for an active substance or excipient are considered. The choice of analytical methods is influenced by their availability, the level of control required and their transfer reproducibility between laboratories. Some activities of the Pharmacopoeia Discussion Group, involving the European, United States and Japanese Pharmacopoeias, and their present status are surveyed.