Breathing in the smell of dirt may lift your spirits, according to a study that found that a bacteria commonly found in soil produces effects similar to antidepressant drugs.

The harmless bacteria, Mycobacterium vaccae, stimulated the release of serotonin in the brain after it was injected into mice. Low levels of serotonin is what causes depression in people.

In a human test, cancer patients reported increases in their quality of life when they were treated with the bacteria.

The findings "leave us wondering if we shouldn’t all be spending more time playing in the dirt,” lead author Chris Lowry of the University of Bristol in England said in a statement.