For a long time the US constitution was interpreted to ensure a right to ingest whatever you like. Nixon was the first to be explicit about banning drugs: the “War on Drugs”.

Interestingly, many US states actually sell tax stamps with specific tax rates for all kinds of illegal drugs. If you sell drugs on which you haven’t paid the tax, you may get a criminal charge but on top of that you get done for tax evasion. They lock you up and they take all your money.

More info here:

If you try to buy the stamps, you have a different kind of problem…