This bill amends Section 280E of the Internal Revenue Code of 1986 to explicitly prohibit tax deductions and credits for businesses trafficking in marijuana. The legislation clarifies that this prohibition applies if such trade or business, or its activities, are prohibited by Federal law or the law of any State in which it operates. By specifically listing marijuana alongside other Schedule I and II controlled substances, the bill aims to maintain the current federal tax treatment for these businesses. This ensures that even businesses operating legally under state laws cannot claim standard business deductions due to the continued federal prohibition of marijuana. The amendment will apply to amounts paid or incurred after the date of its enactment.