Vervain has a very broad spectrum of activity, which is probably due to the iridoid glycosides, their metabolites and verbascoside. Extracts of the plant have antimicrobial, antiviral, antitussive, secretolytic (liquefying bronchial secretions), immunostimulant, and anti-inflammatory effects.
The bitter taste of the herb and its associated use as a digestive aid is also thought to be due to iridoids. However, the efficacy of verbena has yet to be proven by clinical trials.
Vervain: interactions and side effects
Currently, there are no known side effects or interactions with other agents when taking vervain preparations. Also, contraindications have not been demonstrated to date.
