The guidelines have been developed primarily to assist national authorities in introducing a regulatory framework to deal with situations in which patients under treatment with preparations containing internationally controlled drugs are travelling abroad and carrying with them small quantities of such preparations for personal use. Such regulations would enhance the security of patients by making them aware of national requirements in the country they intend to visit. The guidelines also present elements of unified procedures that can be implemented by national authorities responsible for the control of narcotic drugs and psychotropic substances. A wide application of those procedures would facilitate both the mutual disclosure of relevant information through INCB and the work of government authorities. However, it should be understood that countries have latitude to implement the guidelines only partially or with suitable modifications, depending on their legal requirements and practical considerations.