Common horehound, also known as white horehound or Marrubium vulgare, is an herbaceous perennial plant that is commonly used in herbal medicine. It is a member of the mint family and has a distinctively bitter taste. There are several other words that can be used as synonyms for common horehound, including Marrubium, hoarhound, and woolly mint. Additionally, it is sometimes referred to as common houndstongue or bull's blood, although these terms are less common. Regardless of the name, common horehound has been used for centuries for its medicinal properties, specifically in the treatment of respiratory-related ailments such as coughs and asthma.