# Cancer-sniffing animals?

**URL:** <https://boards.straightdope.com/t/cancer-sniffing-animals/308509>\
**Category:** In My Humble Opinion\
**Created:** [June 16, 2005, 7:39am UTC](https://boards.straightdope.com/t/cancer-sniffing-animals/308509 "2005-06-16T07:39:29Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Large\_Marge](https://avatars.discourse-cdn.com/v4/letter/l/50afbb/32.png) [@Large\_Marge](https://boards.straightdope.com/u/Large_Marge)\
**Post date:** [June 16, 2005, 7:39am UTC](https://boards.straightdope.com/t/cancer-sniffing-animals/308509/1 "2005-06-16T07:39:29Z")

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I was reminded by [this post](http://boards.straightdope.com/sdmb/showpost.php?p=6266745&postcount=32) of a show I saw a few years ago that reported that some animals can determine when, and sometimes _where_ a person is ailing. Through a variety of tests–that I can no longer recall, of course–researchers determined that some animals can pinpoint illnesses such as cancer, as[this story](http://www.sfgate.com/cgi-bin/article.cgi?f=/chronicle/archive/2003/06/01/CM38469.DTL) suggests.

Has anyone had any such experiences? Or do they have any links on the subject they’d like to share?

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**Author:** ![Sarah\_Woodruff](https://avatars.discourse-cdn.com/v4/letter/s/df788c/32.png) [@Sarah\_Woodruff](https://boards.straightdope.com/u/Sarah_Woodruff)\
**Post date:** [June 16, 2005, 9:30am UTC](https://boards.straightdope.com/t/cancer-sniffing-animals/308509/2 "2005-06-16T09:30:18Z")

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I have heard anecdotal evidence and I think there was a _New Scientist_ article about the subject, that there have been cases of pet dogs repeatedly sniffing at and worrying at a particular mole or spot on their owner’s skin. Owner goes to the doctor to have it examined, and lo and behold, the mole or spot turns out to be cancerous.  
I think there are more things in Heaven and Earth, Horatio…

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**Author:** ![MLS](https://avatars.discourse-cdn.com/v4/letter/m/919ad9/32.png) [@MLS](https://boards.straightdope.com/u/MLS)\
**Post date:** [June 16, 2005, 5:25pm UTC](https://boards.straightdope.com/t/cancer-sniffing-animals/308509/3 "2005-06-16T17:25:19Z")

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The problem with anecdotal evidence is, we don’t see or hear about the negatives.

Case 1: The dog repeatedly sniffs at a mole or other skin lesion, person visits doctor, doctor determines it’s a harmless freckle.

Case 2: The dog completely ignores a skin defect, which later turns out to be deadly melanoma, which metastasizes; person dies, dog doesn’t give a dam.