The effect of alcohol or say cigarettes is cumulative. You won't die from smoking one or two cigarettes or taking a couple shots of vodka. In my mind this should be reserved for if someone is literally selling deadly poison, that is not labelled as deadly poison, not just something that's bad for you. I'd even go as far as saying I'd support people being able to buy suicide pills or something along those lines as long as they knew what it was. But not, "Miracle pill" that actually just paralyzes you or kills you or gives you debilitating brain damage.