Controlled substances: Importation is the act of bringing certain drugs or controlled substances into the United States without prior approval from the Drug Enforcement Administration (DEA). Controlled substances are divided into five schedules, and depending on the type of controlled substance, the import of the drug may be allowed, restricted, or prohibited. There are two types of controlled substances: Importation: 1. Scheduled Importation: This type of importation is regulated by the DEA and requires an importer to obtain prior approval before importing any controlled substances. The importer must be registered with the DEA and must provide documentation such as invoices, bill of lading, and manifests for the importation of these drugs. 2. Unscheduled Importation: This type of importation does not require prior approval from the DEA, but the importer must still provide the required documentation and be registered with the DEA. The importer must also comply with all other applicable laws and regulations.