It will basically set up a regulatory regime whereby any recreational drug which can be proven "low risk" can be sold to anyone over the age of 18. Not really all that different from how "regular" pharmaceutical drugs are tested and approved, actually.
Because marijuana is a schedule 1 drug it's rather hard to study. Not that it should matter because any adult should be able to put whatever they want in their body.
http://en.wikipedia.org/wiki/Psychoactive_Substances_Bill
It will basically set up a regulatory regime whereby any recreational drug which can be proven "low risk" can be sold to anyone over the age of 18. Not really all that different from how "regular" pharmaceutical drugs are tested and approved, actually.