St. John's Wort is by far the most widely-used and well-studied herbal antidepressant. A number of other herbs have been used traditionally to treat depression and related ailments like anxiety, but the research on most of these treatments is sparse.
Saffron (Crocus sativus L.) has been found in a double-blind randomized clinical trial to be equally effective with imipramine for treating mild to moderate depression; the study also remarked that anticholinergic side effects were more frequent in the imipramine treatment group. Another 8-week double-blind randomized trial found saffron to have a similar effect to fluoxetine (Prozac) in the treatment of mild to moderate depression, including a similar remission rate and similar rate of side effects.
Lavender, Lavandula angustifolia, has been traditionally used to treat depression, although until recently there was little research on this plant. A 2003 double-blind, randomized clinical trial compared lavender to imipramine in the treatment of mild to moderate depression, testing both each treatments individually, and a combination of the two. Lavender was found to be less effective than imipramine, but the combination of both treatments was found to be more effective than either alone.
Several plants in the Salvia genus have been studied for antidepressant properties, although most of the research conducted so far has only been from mice and rat studies. Salvia elegans, also known as pineapple sage, is widely used in Mexican traditional medicine, and has been found in single study in mice to have antidepressant and antianxiety properties.Salvia sclarea, also known as clary, is known to have an antidepressant-like effect in rats, which is thought to be explained by modulation of dopamine.
Ocimum tenuiflorum, also known as Tulsi or holy basil, has been used in Ayurveda to treat anxiety and depression, and was shown in a clinical study to be effective at treating generalized anxiety disorder and depression.
Wormwood, Artemisia absinthium, has shown antidepressant effects in mice, similar activity to imipramine.