Treatment guidelines are disease oriented and reflect a consensus on the treatments of first choice for a range of medical conditions. A formulary manual is drug oriented and contains summary drug information on a selected number of medicines, sometimes combined with practical prescribing and dispensing information. They can both be developed for various levels of health care. The process of developing these publications (the formulary process) is a continual effort, not limited to the one-time production of a set of treatment guidelines or a formulary manual. The process includes gaining acceptance of the concept, preparing a text on the basis of wide consultation and consensus building, implementing an introductory campaign and training activities, and undertaking regular reviews and updates. Treatment guidelines can be made for one institution, such as a hospital; for one level of care, such as all health centers; or for a region or nation. Treatment guidelines are powerful tools to promote rational prescribing, provided they are based on extensive involvement of the end users. Their development is a good opportunity to integrate technical advice from various disease programs into an overall training program. Treatment guidelines should be used as the basis for undergraduate medical and paramedical training, for in-service training, for supervision, and for medical audit. The range of medicines included should be limited to those on the national list of essential medicines. A formulary manual, whether at a national or facility level, should be developed by a formulary subcommittee of the national drug committee or the facility’s drug and therapeutics committee. Both committees should ensure the full participation of prominent specialists and health opinion leaders in the process. One or two editors should be commissioned to draft and edit the formulary manual. To maintain the credibility of the information, a system for regular updates and for incorporation of accepted amendments into the next edition is essential for both formularies and treatment guidelines. This chapter builds on concepts introduced in Chapter 16, which should be read first.