Most are native to Europe, Asia, and North Africa, but Prunella vulgaris (the Common Self-heal) is Holarctic in distribution, occurring in North America as well, and is a common lawnweed. Self-heals are low-growing plants, and thrive in moist wasteland and grass, spreading rapidly to cover the ground. They are members of the mint family and have the square stem common to mints.
While most of the traditional uses are clinically untested and of unknown efficacy, Prunella vulgaris has been shown to have pharmacological effects in vitro and in some animal models as an antioxidant, immune stimulant, viral replication inhibitor and an anti-inflammatory agent.P. vulgaris and P. asiatica have shown some anti-(lung)cancer activity in vitro.
^Immune modulatory effects of Prunella vulgaris L. Int J Mol Med. 2005 Mar;15(3):491-6.
^A polysaccharide fraction from medicinal herb Prunella vulgaris downregulates the expression of herpes simplex virus antigen in Vero cells. J Ethnopharmacol. 2004 Jul;93(1):63-8.
^Phenolics-rich extracts from Silybum marianum and Prunella vulgaris reduce a high-sucrose diet induced oxidative stress in hereditary hypertriglyceridemic rats. Pharmacol Res. 2004 Aug;50(2):123-30.
^Biological activities of Prunella vulgaris extract. Phytother Res. 2003 Nov;17(9):1082-7.
^Anti-allergic and anti-inflammatory triterpenes from the herb of Prunella vulgaris. Planta Med. 2000 May;66(4):358-60.
^Inhibition of immediate-type allergic reactions by Prunella vulgaris in a murine model. Immunopharmacol Immunotoxicol. 2001 Aug;23(3):423-35.
^Feng L, Jia XB, Jiang J, Zhu MM, Chen Y, Tan XB, Shi F"Combination of active components enhances the efficacy of Prunella in prevention and treatment of lung cancer." Molecules. 2010 Nov;15(11):7893-906