# Why does Pepto-bismol turn turds dark colored?

**URL:** <https://boards.straightdope.com/t/why-does-pepto-bismol-turn-turds-dark-colored/777587>\
**Category:** Factual Questions\
**Created:** [January 19, 2017, 11:02pm UTC](https://boards.straightdope.com/t/why-does-pepto-bismol-turn-turds-dark-colored/777587 "2017-01-19T23:02:02Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![janeslogin](https://avatars.discourse-cdn.com/v4/letter/j/df788c/32.png) [@janeslogin](https://boards.straightdope.com/u/janeslogin)\
**Post date:** [January 19, 2017, 11:02pm UTC](https://boards.straightdope.com/t/why-does-pepto-bismol-turn-turds-dark-colored/777587/1 "2017-01-19T23:02:02Z")

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A simple scatological, or is it pharmacological, question. Why does Pepto-bismol turn turds dark colored?

nm ‘’…sulfur in saliva and the colon to form bismuth sulfide.’’

SDMB is good. I find most of my answer while attempting to write the question.

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**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\
**Post date:** [January 20, 2017, 12:46am UTC](https://boards.straightdope.com/t/why-does-pepto-bismol-turn-turds-dark-colored/777587/2 "2017-01-20T00:46:07Z")

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Since you answered your own question, I’ll chime in with a fun fact- bismuth used to be considered the heaviest non-radioactive element, until it was discovered to be [very slightly radioactive.](http://physicsworld.com/cws/article/news/2003/apr/23/bismuth-breaks-half-life-record-for-alpha-decay)