- Oregano, sweet marjoram and dittany are mainly used to help support coughs, catarrh, cough and cold, colic and dyspepsia. These herbs or their dilute oils are sometimes used topically for mouth hygiene, to help support nasal congestion, wounds and itching skin. The essential oils of oregano and marjoram are used in aromatherapy. - Oregano - Origanum vulgare L. - Family: Lamiaceae. - Other Names: Origan (French); Echter Dost (German); origana (Italian); organo (Spanish). - Descript