Ancient Romans Used Urine Mouthwash

While the thought of a urine-based mouthwash is jarring to modern sensibilities, for ancient Romans it was a practical and effective tool for oral hygiene. The secret lies in chemistry: as urine decomposes, the urea within it breaks down into ammonia. This potent chemical is a fantastic natural cleaning agent, capable of disinfecting and acting as a powerful bleaching agent to lift stains from tooth enamel. Lacking modern chemical knowledge, the Romans simply observed the powerful whitening effect of aged, or "stale," urine and put it to use for a brighter smile.

This practice was so widespread that it became a recognized part of the