[waterhouse]

I think there's already a problem with low-quality, impure product being sold on the street w.r.t. illegal drugs. If the drugs were legalized, people would at least have the alternative of buying them legally from a large drug store with a reputation to protect. I imagine the problem you describe would not get worse under legalization.

(Found one source on street drug purity: http://www.drugscope.org.uk/resources/faqs/faqpages/how-pure...)

[DanBC]

That's a great point: I would much rather buy 5% amphetamine 95% sugar from a licensed seller than whatever the hell I'm getting on the street. While contamination with rat poison is mostly a myth contamination can produce nasty results.

Anthrax in injecting heroin users: http://www.bbc.co.uk/news/uk-scotland-glasgow-west-18981196

Glass microbeads in cannabis: http://news.bbc.co.uk/2/hi/uk_news/england/staffordshire/638...

[lostcolony]

It's more than that though. Not just licensing, but motive to self-regulate.

You don't buy "(Cartel X) branded (drug of choice)", so there is no reputation to protect by it; if one batch is bad, meh, no big deal.

Whereas if it's available at a drugstore...CVS and Walgreens compete, and have reputations to maintain. Any contamination not only would have federal implications, but also would have direct economic ones, such that they are incentivized to self-police. To ensure their entire supply line is coming from reputable sources, is randomly tested for contaminants, and anything that slips through leads to a recall. Otherwise, they face a loss of business to the competitor.