# What is a lethal dose of aspirin

**URL:** <https://boards.straightdope.com/t/what-is-a-lethal-dose-of-aspirin/250068>\
**Category:** Factual Questions\
**Created:** [June 13, 2004, 2:13am UTC](https://boards.straightdope.com/t/what-is-a-lethal-dose-of-aspirin/250068 "2004-06-13T02:13:32Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Justin\_Bailey](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/justin_bailey/32/8792_2.png) [@Justin\_Bailey](https://boards.straightdope.com/u/Justin_Bailey)\
**Post date:** [June 13, 2004, 2:13am UTC](https://boards.straightdope.com/t/what-is-a-lethal-dose-of-aspirin/250068/1 "2004-06-13T02:13:32Z")

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Just curious, what is a lethal does in x number of tablets in x amount of time.

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**Author:** ![Qadgop\_the\_Mercotan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/qadgop_the_mercotan/32/83_2.png) [@Qadgop\_the\_Mercotan](https://boards.straightdope.com/u/Qadgop_the_Mercotan)\
**Post date:** [June 13, 2004, 2:22am UTC](https://boards.straightdope.com/t/what-is-a-lethal-dose-of-aspirin/250068/2 "2004-06-13T02:22:55Z")

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Well, for rats the LD 50 (the dose needed to kill half the rats to whom its fed) is 1.2 grams/kg. That would be about 200 grams for a 180 pound man.

Such precise studies have not yet been done on humans. Note however, that lesser doses have killed people.

See this site: [http://www.emedicine.com/EMERG/topic514.htm](http://www.emedicine.com/EMERG/topic514.htm) for more relevant information.

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**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\
**Post date:** [June 13, 2004, 2:28am UTC](https://boards.straightdope.com/t/what-is-a-lethal-dose-of-aspirin/250068/3 "2004-06-13T02:28:05Z")

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It’s a difficult thing to quantify, since different individuals react differently to varying amounts of a given substance. The best indicator we have is called the LD50, which is the dosage at which 50% of individuals (usually test animals, for obvious reasons) die within a 24-hour period. From the MSDS for aspirin, the LD50 (Oral dose, mouse) - is 815 mg of aspirin per kg of body weight. Assuming that scales up to humans, then it would take 65.2 g of aspirin to have a 50/50 chance of killing an 80-kg human. Or about that many 1000 mg tablets.

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**Author:** ![Tim\_T-Bonham.net](https://avatars.discourse-cdn.com/v4/letter/t/46a35a/32.png) [@Tim\_T-Bonham.net](https://boards.straightdope.com/u/Tim_T-Bonham.net)\
**Post date:** [June 13, 2004, 2:44am UTC](https://boards.straightdope.com/t/what-is-a-lethal-dose-of-aspirin/250068/4 "2004-06-13T02:44:01Z")

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No scientific calculations like the previous posters, just the “rule of thumb” mentioned by an experienced friend who works in a very busy Emergency Room:

standard adult aspirin tablets consumed:

- 2 to 3 dozen = risky, but will probably survive
- 4 to 5 dozen = very iffy, might or might not survive
- 6 dozen or more = probably fatal

But that does seem to be a reasonable match with the dosages given by them.