What does the Physicians Desk Reference for Herbal Medicines, 1st edition, say about oregano?
Indications and Usage: The herb is used for respiratory disorders and complaints such as coughs and bronchial catarrh, and as an expectorant. In folk medicine it is used for dyspepsia, painful menstruation, rheumatoid arthritis, scrofula, urinary tract disorders, and as a diaphoretic. Precautions and Adverse Reactions: No health hazards or side effects are known in conjunction with the proper administration of designated therapeutic dosages.