8 February 2012 – From The Atlantic: I’m holding a bowl of dirt up to my nose in hopes of getting high on the fumes of my backyard compost pile. The microbe that I’m after today is M. vaccae, a living creature that acts like a mind-altering drug once it enters the human body.
It has been shown to boost the levels of serotonin and norepinephrine circulating in the systems of both humans and mice. In other words, it works in much the same manner as antidepressant pills. And yes, it is possible to dose yourself by simply breathing in the smell of good dirt.
The drug-like effects of this soil bacteria were discovered, quite by accident, about a decade ago. A doctor named Mary O’Brien created a serum out of the bacteria and gave it to lung-cancer patients, in hopes that it might boost their immune systems.
Instead, she noticed another effect: The hospital patients perked up. They reported feeling happier and suffered from less pain than the patients who did not receive doses of bacteria. Further studies in mice confirmed the mood-boosting effect of the soil bugs.
and thanks to Treehugger for the pointer