Pecunia Non Olet: The Urine Tax of Ancient Rome

A Roman-era latrine in Timgad in Algeria . Credit: Wikimedia Commons Throughout history, governments have found creative ways to raise revenue, taxing everything from the essential to the absurd. Beyond familiar levies like income, property, and sales taxes, there have been taxes on bachelors, beards, hats, bricks, and even windows . In ancient Rome, the tax system included four main pillars: a cattle tax, a land tax, customs duties, and a tax on professional earnings. But Roman ingenuity didn't stop there—widows and orphans could be taxed, as could slave owners who freed their slaves. Among the more unusual and memorable of these levies was the urine tax . Introduced by Emperor Vespasian in the 1st century AD, this malodorous but profitable measure not only helped replenish the imperial treasury, it also gave rise to one of history’s most enduring financial maxims: pecunia non olet —“money does not stink.” To the ancient Romans, urine was far more than waste—it was a valuable commodity. Rich in ammonia, it possessed chemical properties that made it indispensable across several industries. Tanners used it to break down proteins in animal hides, softening the leather and making it more supple. Fullers, or Roman launderers, relied on urine to clean and bleach clothing, especially woollen garments like togas. These were soaked in vats of stale urine and then trampled by workers to loosen dirt and oils. In an age without soap, the ammonia acted as a natural detergent, whitening and deodorizing fabrics. Urine also played a role in dyeing, where it helped fix colours to textiles. Perhaps the most surprising and unsettling use was in oral hygiene. Some Romans believed that urine could whiten teeth and occasionally used it as a mouthwash. With so many practical applications, public urinals became a crucial resource for craftsmen and merchants. Ancient Roman latrines in the ancient city Ostia Antica, Italy.