Seattle's city council voted unanimously to decimalize psilocybin—the psychoactive compound in psychedelic mushrooms—and related plant-derived drugs like ayahuasca, Bloomberg reports. While these substances remain technically illegal, the city's police department has been ordered to make enforcement among their lowest priorities. 

The vote made Seattle the largest city to decriminalize these drugs, but it's far from the first: Denver kicked off a trend of cities passing decriminalization measures three years ago and now at least 9 municipalities have followed suit, including both big coastal cities (Oakland; Washington, D.C.) and smaller towns inhabited by a lot of hippies (Easthampton, Massachusetts).  

It's all part of rising wave of a growing acceptance of psychedelic drugs in America, fueled by promising results treating a variety of mental health concerns in clinical trials, a desire to wind down the war on drugs, and Michael Pollan. 

But advocates remain split on exactly how these drugs should be legalized. Last year, Oregon voters passed a ballot measure legalizing psilocybin—but only as administered by a trained guide in a controlled setting. (In a separate ballot measure, the same voters decriminalized virtually all drugs.) The first measure was opposed by some drug legalization advocates, who fear a psychedelic “gold rush" from investors and pharmaceutical companies. That would likely require action at the federal level. For now, at least, you simply won't get busted buying shrooms on Craigslist in Seattle. 

Read MoreOregon Is on the Verge of Legalizing Shrooms Therapy, Thanks to Your Favorite Hippie Soap

If Measure 109 passes on Tuesday, anyone in the state will soon be able to take a therapeutic psilocybin trip with a trained guide.

By Colin Groundwater

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