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. Credit: Wikimedia Commons

Sensing an opportunity, Emperor Vespasian, who ruled from AD 69 to 79, introduced a tax on the collection of urine from these public latrines. Those who gathered it for commercial purposes had to pay a fee to the state. It was a practical move to generate revenue in the aftermath of civil war and the costly rebuilding of Rome, but it wasn’t universally admired.

According to the Roman historian Suetonius, Vespasian’s son Titus objected to the tax, finding the idea of profiting from human waste unseemly. In response, Vespasian is said to have held a coin up to Titus’s nose and asked whether it smelled. When Titus replied that it did not, the emperor retorted, “Yet it comes from urine.”

With that, the phrase pecunia non olet—literally, “money does not stink”—was born. It became a pointed reminder that the value of money is not tainted by its origins.

Surprisingly, the legacy of the urine tax endures. In France, public urinals were historically known as vespasiennes, a nod to the emperor who monetized bodily functions. And the phrase pecunia non olet remains part of the modern lexicon, used to convey that money retains its value regardless of how it was earned.

In a world where the ethics of wealth accumulation are regularly debated, the Roman urine tax offers a pungent, if practical, lesson from history: no matter its source, money has no smell.