Ancient Romans Used Urine for Teeth

The Roman Empire Built on Piss

In ancient Rome, the emperor Vespasian was approached by his son Titus, who objected to a new tax the emperor had imposed. The tax was on urine. Public latrines and private collectors gathered the contents of Rome's chamber pots and sold it to fulleries, where it was used to clean wool and to launder the heavy togas that Roman citizens wore. The trade was lucrative. Vespasian saw no reason not to tax it.

Titus thought the tax was beneath the dignity of the empire. Vespasian picked up a coin from the first payment, held it to his son's nose, and asked: "Does it smell?" Titus said no. Vespasian replied: "And yet it comes from urine." The exchange was recorded by the historian Suetonius. The phrase "Pecunia non olet"—money does not stink—became a proverb.

The Romans did not only tax urine. They used it. They used it to whiten their teeth, to clean their clothes, to tan leather, and to bleach wool. The practice was not a secret. It was a industry. The Romans who rinsed their mouths with urine were not desperate or primitive. They were using the best chemical they had.

What Everyone Knows

The Roman Empire is remembered for its engineering, its law, its literature, and its military. The image of a Roman citizen is one of marble togas, aqueducts, and forums. The Romans were sophisticated. They bathed regularly, used public latrines, and built sewer systems that would not be matched for a thousand years.

What is less often emphasized is that their sophistication did not extend to modern chemistry. They did not have synthetic detergents. They did not have bleaching agents. They had ammonia, and the best source of ammonia they had was stale urine. They used it because it worked.

What History Actually Shows

The Roman fullery, or fuller's shop, was an essential part of the urban economy. Wool, after it was sheared and woven, needed to be cleaned and thickened. The process, called fulling, involved soaking the cloth in a mixture of water and urine, then stomping on it or beating it to work the fibers. The ammonia in the urine acted as a detergent, removing grease and dirt. It also bleached the cloth, making it whiter.

The demand for urine was constant. Fulleries placed collection pots on street corners. Public latrines were designed with collection systems. The urine was aged, because aged urine produced more ammonia. The smell was, by all accounts, overwhelming. The fullers were not a respected class, but they were necessary.

The use of urine for dental hygiene is also documented. The Roman poet Catullus mocked a man whose teeth were so clean they looked like they had been "scraped with Spanish piss." The medical writer Scribonius Largus recommended a mouthwash of urine mixed with pumice for tooth whitening. The Roman elite, who could afford imported tooth powders and pastes, may have avoided the practice. The lower classes used what was available.

The tax that Vespasian imposed was not a tax on urine itself but on the trade in urine. The fulleries, which purchased urine from collectors, paid a levy on their transactions. The tax was not a novelty. The Romans taxed everything: imports, exports, sales, inheritances, and slaves. The urine tax was notable only because of the emperor's exchange with his son.

The Part That Got Buried

The Roman urine trade was not a marginal industry. It was central to the textile economy. Rome's woolen industry, one of the largest in the empire, depended on fulling. Without ammonia, the wool could not be cleaned and finished. The fulleries that processed the wool employed hundreds of workers. The collectors who supplied them operated across the city. The trade was regulated, taxed, and essential.

The urine used in fulleries came from humans, not animals. Animal urine, the Romans knew, did not work as well. Human urine, particularly from men who ate a diet rich in protein, produced the highest concentration of ammonia. The collectors who supplied the fulleries were known to prefer the urine of young men who had been drinking wine. The quality varied. The price reflected it.

The practice of using urine for dental hygiene declined as the Roman economy changed. The collapse of urban life in the West in the 5th and 6th centuries ended the fulling industry that had supported the trade. The knowledge that ammonia could whiten teeth and clean cloth was not lost, but the industry that collected and distributed it disappeared. The medieval fullers who revived the trade in the 12th century used stale urine, just as the Romans had.

The Ripple Effect

The phrase "money does not stink" survived the empire that produced it. Vespasian's exchange with his son became a proverb used to justify distasteful but necessary revenue sources. The image of the emperor holding a coin to his son's nose became a symbol of practical governance: revenue is revenue, regardless of its source.

The Roman urine trade is now remembered as a curiosity, a footnote in the history of sanitation and hygiene. But it was not a footnote at the time. It was a major industry, employing thousands, generating tax revenue, and supplying essential services to the city. The Romans did not find it strange. They found it necessary.

The Line That Says It All

Vespasian's tax on urine was so profitable that his son objected on the grounds that it was beneath the dignity of the empire, and Vespasian proved him wrong by showing him that the coin made from the tax smelled the same as any other coin—and the empire that built aqueducts and roads and a legal system that still shapes the world was also an empire where the government's revenue depended on the contents of the public latrines.