Any illegal marijuana or controlled substance must have a marijuana or controlled substance stamp on the package.
A person who, in violation of Minnesota law, manufactures, sells, or is in possession of unstamped marijuana or controlled substance must purchase stamps from the Department of Revenue. (Minnesota Statute 297D,)
There is no guarantee you will not be prosecuted if you pay taxes on marijuana or controlled substances. However, information in Minnesota Department of Revenue tax reports or returns cannot be used against you in a criminal court proceeding unless someone else obtains the information independently. The information CAN be used in a criminal court proceeding if it involves taxes you owe under the statute.