A tax shall be imposed on marihuana and controlled substances as defined in section one of Massachusetts General Laws Chapter 64K at the following rates:

(1) on each gram of marihuana, or each portion of a gram, three dollars and fifty cents; and
(2) on each gram of controlled substance, or portion of a gram, two hundred dollars; or (3) on each fifty dosage units of a controlled substance that is not sold by weight, or a portion thereof, two thousand dollars.

When a dealer purchases, acquires, transports, or imports into the Commonwealth marihuana or controlled substances on which a tax is imposed by section eight and, if the indicia evidencing the payment of the tax has not already been affixed thereto, the dealer shall have them permanently affixed on the marihuana or controlled substance immediately after receiving such marihuana or controlled substance. Each stamp or other official indicia shall be used only once.

The statute provides that taxes imposed upon marihuana or controlled substances by this chapter are due and payable immediately upon acquisition or possession in the Commonwealth by a dealer.

Official stamps, labels, or other indicia to be affixed to all marihuana or controlled substances shall be purchased from the commissioner. The purchaser shall pay one hundred percent of face value for each official stamp, label, or other indicia at the time of such purchase.

However, in 1998 the Supreme Judicial Court ruled that assessment of the 64K tax on a person convicted criminally of illegal possession of marihuana or controlled substances constituted impermissible double jeopardy under the United States Constitution.  Commissioner of Revenue v. Mullins (1998) 702 N.E.2d 1, 428 Mass. 406.  That SJC decision held that the Fifth Amendment does not prevent imposition of the tax, but rather it restricts the ability of the Commonwealth to assess the tax against those who have suffered criminal penalties for the same possession of marihuana or controlled substances.