Blue Vervain is a North American herb used for centuries by Native Americans. It is primarily taken as a general tonic, but is also used for some specific conditions. It is an effective expectorant. It prevents or eliminates worms. It is used to cure diarrhea. It is used to fight fevers and ulcers. It aids in passing kidney stones. It fights urinary tract infections. It is a mild sedative and sleep-aid. It is sometimes used for colds and cough. It relieves respiratory and liver congestion. It is used for all diseases of the liver and spleen. It aids in removing toxins from the skin by inducing sweating. It aids menstrual flow and can aid women in increased milk flow. It is an aid to poor circulation. 
    As a poultice, Blue Vervain is used to treat headaches and arthritis. In strong doses, it can induce vomiting. It is also used externally on wounds, burns and sores. Some believe it is useful for cancers, but more research is needed in that area. It should not be taken by pregnant women.