Under federal law (applicable in all states) it is illegal for a person to knowingly or intentionally possess a controlled substance, unless the substance was obtained through a valid prescription or order from a practitioner, while acting in the course of the practitioner’s professional practice. See 21 U.S.C. §844.

The term controlled substance means a drug or other substance—or an immediate precursor to the drug or other substance—that is included in schedule I, II, III, IV, or V of the relevant portion of the United States Code (statute). See 21 U.S.C. §841.

The term practitioner means a physician, dentist, veterinarian, scientific investigator, pharmacy, hospital, or other person licensed, registered, or otherwise permitted by the United States or the jurisdiction (state) in which he practices or does research to distribute, dispense, conduct related research, administer, or use in teaching or chemical analysis a controlled substance in the course of such professional practice or research. 21 U.S.C. §802(21).

As under federal law, state laws usually classify substances in groups or schedules that determine which substances are included in the definition of controlled substances, and the potential penalties or punishments for possessing them without legal authorization. Criminal charges and penalties for these offenses vary from state to state and are usually located in a state’s statutes—often in the penal or criminal code. Illegal possession of controlled substances may also be prosecuted under federal law. See 21 U.S.C. §844.

Under both federal and Minnesota state law, it is illegal to knowingly or intentionally possess a controlled substance without a valid prescription or order from a licensed practitioner. Controlled substances are classified into schedules I through V, with Schedule I substances being considered the most dangerous and having no accepted medical use, and Schedule V substances being considered the least dangerous with lower potential for abuse. In Minnesota, the specific statutes that address controlled substances are found in Chapters 152 of the Minnesota Statutes. Penalties for possession vary depending on the amount and type of substance, as well as other factors such as prior offenses. Possession of a small amount of marijuana, for example, is treated less severely than possession of narcotics like heroin or methamphetamine. It's important to note that while state laws may vary, federal law also prohibits the possession of controlled substances, and individuals can be prosecuted under federal law, which may carry different or additional penalties.