Blue Vervain (Verbena hastata) has a long history of use in traditional herbal medicine, particularly within Native American and European herbal practices, for supporting emotional well-being and easing symptoms associated with worry, anxiety, and nervous tension. Traditional herbalists have regarded Blue Vervain as a mild nervine—an herb that purportedly calms the nervous system and helps to relieve restlessness, anxious feelings, and insomnia related to mental stress.

Despite its longstanding reputation, there is a lack of robust scientific studies directly investigating Blue Vervain's efficacy for treating worry or anxiety. Most of the available evidence is anecdotal or comes from historical herbal texts. The plant contains various phytochemicals, such as iridoid glycosides (notably verbenalin) and flavonoids, which in laboratory studies have shown some potential for central nervous system effects, but these findings have not translated into clinical trials demonstrating effectiveness for worry or anxiety in humans.

In summary, the use of Blue Vervain to support or treat worry is primarily justified by traditional use rather than scientific validation. The quality of evidence is modest, based largely on historical usage rather than controlled clinical studies.