This section is from the book "Botanic Drugs Their Materia Medica, Pharmacology and Therapeutics", by Thomas S. Blair. Also available from Amazon: Botanic Drugs, Their Materia Medica, Pharmacology and Therapeutics.
Horehound (hoarhound), Marrubium vulgare. Official in Japan and the U. S. P. VIII.
Stimulant, tonic, and slightly laxative. Warm infusions produce diaphoresis. The cold infusion is a bitter tonic. In the form of a syrup it is regarded as a tonic expectorant. The fl. may be given in doses of 20 to 30 minims.