" Saffron The earliest recorded medical use of a spice appears to be more than 3,600 years ago, when saffron was evidently first used for healing.43 A few thousand years later, scientists finally put saffron to the test in a head-to-head trial against the antidepressant drug Prozac for the treatment of clinical depression. Both the spice and the drug worked equally well in reducing depression symptoms.44 As you can see in the box here, this may not be saying much, but at the very least, the saffron was safer in terms of side effects. For example, 20 percent of people in the Prozac group suffered sexual dysfunction, a common occurrence with many antidepressant medications, whereas no one in the saffron group did. However, saffron may be one of those rare cases in which the natural remedy is more expensive than the drug. Saffron is the world’s most expensive spice. It is harvested from crocus flowers, specifically the dried stigmas "

― Michael Greger , How Not to Die: Discover the Foods Scientifically Proven to Prevent and Reverse Disease