buzzfeed The Romans used to clean and whiten their teeth with urine. Apparently it works.

Is this true?

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    There are two claims here: 1) did they use urine, and 2) did it work? Are you asking about both? – Reinstate Monica -- notmaynard Oct 9 '14 at 22:43
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    Note that urine (of a healthy person) a) is sterile, b) may be abrasive. Abrasivness it how you get rid of plaque, and sterility helps against infection etc., obviously very handy if you don't have clean water. Was it actually used by the Romans? Who knows. It was definitely used as slander, though - which implies it was at least a controversial practice, if used at all. – Luaan Oct 22 '14 at 13:20

According to wikipedia and the sources cited there, yes they did. And yes it worked. Urine contains urea, which decomposes into ammonia, which is a modern day cleaner, and is even used in lots of toothpaste.

It seems to be used more as a whitener than a cleaning agent. The Roman poet Catullus wrote of it. People are still using it in rare cases.

Here's a video about it. Romans used urine to clean and whiten their teeth, they collected urine, and used it for many other purposes. They even enacted taxes on it.

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    Welcome to Skeptics! This answer would be improved by not relying directly on Wikipedia but instead following up on the references, and quoting some of their findings to mitigate link rot. You should also provide evidence that toothpastes contain ammonia, that it is in toothpaste for its cleaning properties, and that it works as such. – Oddthinking Oct 10 '14 at 1:01
  • FWIW, the references I've run into seem to suggest that ammonia, in the form of urea, was in use through the 1980s, but has declined except in the use in some whitening toothpastes. – Sean Duggan Oct 10 '14 at 12:30
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    Ammonia != urea. Urine contains urea, not ammonia. Urea in solution does slowly decompose into ammonia, but the two are not the same. I would guess that ammonia (ammonium hydroxide), not urea, is included in some toothpastes as a pH buffer, not a cleaning agent. – Reinstate Monica -- notmaynard Oct 17 '14 at 22:10
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    This is a poor answer. The Wikipedia page itself says nothing about this claim; the relevant reference in that page only states, "First-century Roman physicians advocated brushing teeth with Portuguese urine to achieve a whiter appearance." That reference gives no citation for that claim, no further evidence that it was practiced, no evidence as to whether it actually worked. Furthermore, this answer still gives no evidence concerning urea/ammonia, as @Oddthinking pointed out. – Reinstate Monica -- notmaynard Sep 28 '15 at 22:04
  • According to a Reddit thread on AskHistorians, the poems by Catullus are claims that Iberians clean their mouths with urine—not Romans. – Nick Matteo Apr 7 '20 at 0:25

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