# Coumadin is rat poison? Really? **URL:** \ **Category:** Factual Questions\ **Created:** [October 11, 2001, 3:11am UTC](https://boards.straightdope.com/t/coumadin-is-rat-poison-really/86722 "2001-10-11T03:11:53Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![Catfood\_Purrito](https://avatars.discourse-cdn.com/v4/letter/c/c6cbf5/32.png) [@Catfood\_Purrito](https://boards.straightdope.com/u/Catfood_Purrito)\ **Post date:** [October 11, 2001, 3:11am UTC](https://boards.straightdope.com/t/coumadin-is-rat-poison-really/86722/1 "2001-10-11T03:11:53Z")
In a note I transcribed this evening, the doctor dictated that the patient refused to take Coumadin (warfarin), because it is a rat poison. Is that true? How would that work, Coumadin is a blood thinner, right? So, what, the rats eat the stuff and we hope they get a cut and bleed to death? ---
**Author:** ![Reeder](https://avatars.discourse-cdn.com/v4/letter/r/c6cbf5/32.png) [@Reeder](https://boards.straightdope.com/u/Reeder)\ **Post date:** [October 11, 2001, 3:22am UTC](https://boards.straightdope.com/t/coumadin-is-rat-poison-really/86722/2 "2001-10-11T03:22:10Z")
Coumadin, which is used as a blood thinner is also effective in poisoning rats (by causing them to bleed to death internally). So it doesn’t poison them. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [October 11, 2001, 3:41am UTC](https://boards.straightdope.com/t/coumadin-is-rat-poison-really/86722/3 "2001-10-11T03:41:19Z")
From the Wisconsin Alumni Research Foundation ([WARF](http://www.wisc.edu/uir/WARF.html)) site: > [@](#): > > (in 1947)…Link and his co-workers isolated dicoumarin, the agent in spoiled sweet clover that causes cattle to hemorrhage. The discovery led to the synthesis of Dicumarol, the first anticoagulant that could be administered to humans orally, which brought new understanding of the blood clotting mechanism. The successor to Dicumarol was Warfarin (named after WARF) which became an international household word after it was introduced as a rodenticide. Warfarin’s unprecedented effectiveness in controlling pestilent rats and mice, along with an unsurpassed human safety record, led to its widespread success. Additionally, sodium Warfarin became the most widely prescribed anticoagulant drug in the nation. It’s not uncommon for biologically active compounds to have a variety of uses. ---
**Author:** ![Catfood\_Purrito](https://avatars.discourse-cdn.com/v4/letter/c/c6cbf5/32.png) [@Catfood\_Purrito](https://boards.straightdope.com/u/Catfood_Purrito)\ **Post date:** [October 11, 2001, 3:50am UTC](https://boards.straightdope.com/t/coumadin-is-rat-poison-really/86722/4 "2001-10-11T03:50:29Z")
That’s really interesting. Thanks! ---
**Author:** ![MsRobyn](https://avatars.discourse-cdn.com/v4/letter/m/90ced4/32.png) [@MsRobyn](https://boards.straightdope.com/u/MsRobyn)\ **Post date:** [October 11, 2001, 4:19am UTC](https://boards.straightdope.com/t/coumadin-is-rat-poison-really/86722/5 "2001-10-11T04:19:31Z")
I should point out that humans on warfarin are usually closely followed for bleeding problems. Usually, they go in for bloodwork every week or two. Robin ---
**Author:** ![CurtC](https://avatars.discourse-cdn.com/v4/letter/c/ce73a5/32.png) [@CurtC](https://boards.straightdope.com/u/CurtC)\ **Post date:** [October 11, 2001, 4:52am UTC](https://boards.straightdope.com/t/coumadin-is-rat-poison-really/86722/6 "2001-10-11T04:52:10Z")
As with many things, “the dose makes the poison.” Chlorine and Fluorine are poisons, but we put them in our drinking water. Tylenol is a great fever reducer and pain reliever, but take too much and it kills you. Just about everything you might take as medicine would be poisonous at higher doses. I was listening to The People’s Pharmacy, a call-in show on public radio, and a man called and complained that his wife’s doctor had prescribed Coumadin, which is a rat poison, and he sounded pretty ticked off about it. The hosts of the show effectively did a big “duh!” and explained that the dose makes the poison. Since your doctor’s patient had heard the same thing about Coumadin, there might be some wacko conspiracy circles that circulate this BS… Yep, I just did a web search, and the wackos responsible for this one are the alternative medicine people. Here’s a quote: _“I would no more put coumadin in my body than Rat Poison. Why? They are the same thing. Coumadin is one of the main ingredients in rat poison. If you need to thin your blood, please find a Naturopath who can help you by using natural blood thinners, like high doses of vitamin E, for example.”_ ---
**Author:** ![mmmiiikkkeee](https://avatars.discourse-cdn.com/v4/letter/m/edb3f5/32.png) [@mmmiiikkkeee](https://boards.straightdope.com/u/mmmiiikkkeee)\ **Post date:** [October 11, 2001, 6:58am UTC](https://boards.straightdope.com/t/coumadin-is-rat-poison-really/86722/7 "2001-10-11T06:58:24Z")
Yeah, it’s essentially watered-down rat poison; my dad takes it, and he was the first to point that out. He goes in for blood tests every now and then, but has been fine for years. ---
**Author:** ![inquisitive\_blee](https://avatars.discourse-cdn.com/v4/letter/i/13edae/32.png) [@inquisitive\_blee](https://boards.straightdope.com/u/inquisitive_blee)\ **Post date:** [October 2, 2013, 7:54pm UTC](https://boards.straightdope.com/t/coumadin-is-rat-poison-really/86722/8 "2013-10-02T19:54:36Z")
> [@mmmiiikkkeee](#): > > Yeah, it’s essentially watered-down rat poison; my dad takes it, and he was the first to point that out. He goes in for blood tests every now and then, but has been fine for years. My father in law is now in a nursing home because he was bleeding internally from taking this poison and was incapacitated for a few weeks. It has weakened his muscles so much that he must now go through rehabilitation because he can’t stand on his own two feet. I wouldn’t touch this “medicine aka poison” with a ten foot pole… ---
**Author:** ![Frazzled](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/frazzled/32/3368_2.png) [@Frazzled](https://boards.straightdope.com/u/Frazzled)\ **Post date:** [October 2, 2013, 7:58pm UTC](https://boards.straightdope.com/t/coumadin-is-rat-poison-really/86722/9 "2013-10-02T19:58:47Z")
Not only can Warfarin kill small rats, it’s thought to have killed some mighty big rats as well! There’s a not very far fetched theory that it was used to kill Stalin. > **[New Study Supports Idea Stalin Was Poisoned (Published 2003)](https://www.nytimes.com/2003/03/05/world/new-study-supports-idea-stalin-was-poisoned.html?pagewanted=all&src=pm)** > > Study of long-secret Soviet records lends new weight to old theory that Josef Stalin, who died of brain hemorrhage 50 years ago, was actually poisoned, perhaps to avert looming war with US; new book Stalin's Last Crime, by Vladimir P Naumov and... ---
**Author:** ![Inner\_Stickler](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/inner_stickler/32/318_2.png) [@Inner\_Stickler](https://boards.straightdope.com/u/Inner_Stickler)\ **Post date:** [October 2, 2013, 7:59pm UTC](https://boards.straightdope.com/t/coumadin-is-rat-poison-really/86722/10 "2013-10-02T19:59:52Z")
I’m sure 2001 is suitably distraught. ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [October 2, 2013, 8:05pm UTC](https://boards.straightdope.com/t/coumadin-is-rat-poison-really/86722/11 "2013-10-02T20:05:58Z")
We’ve been Stalin for time. ---
**Author:** ![want2befree](https://avatars.discourse-cdn.com/v4/letter/w/3e96dc/32.png) [@want2befree](https://boards.straightdope.com/u/want2befree)\ **Post date:** [October 2, 2013, 8:07pm UTC](https://boards.straightdope.com/t/coumadin-is-rat-poison-really/86722/12 "2013-10-02T20:07:21Z")
Does it kill zombies? 12 year old zombies more specifically? ---
**Author:** ![bump](https://avatars.discourse-cdn.com/v4/letter/b/7c8e57/32.png) [@bump](https://boards.straightdope.com/u/bump)\ **Post date:** [October 2, 2013, 8:07pm UTC](https://boards.straightdope.com/t/coumadin-is-rat-poison-really/86722/13 "2013-10-02T20:07:57Z")
> [@inquisitive\_blee](#): > > My father in law is now in a nursing home because he was bleeding internally from taking this poison and was incapacitated for a few weeks. It has weakened his muscles so much that he must now go through rehabilitation because he can’t stand on his own two feet. I wouldn’t touch this “medicine aka poison” with a ten foot pole… Did you not read the posts above? Like they said, the dose determines the poisonousness. A little salt is poisonous to bacteria, but not to us, and is actually necessary. Yet, when you eat salty foods, you’re eating a disinfectant of sorts. The reason they prescribe coumadin/warfarin for preventing and treating strokes and heart attacks is the EXACT SAME reason that it is lethal to rats. It’s beneficial in the small amounts used as an anticoagulant, and lethal to rats in the dosages they eat as a poison. I suspect with the right dosage, it would be an effective anticoagulant in living rats as well. What’s more, any sort of anticoagulant will work in much the same way, unless it’s human-specific. Even the large doses of vitamin E someone mentioned above would likely either kill or mess up the rat. ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [October 2, 2013, 8:11pm UTC](https://boards.straightdope.com/t/coumadin-is-rat-poison-really/86722/14 "2013-10-02T20:11:22Z")
This thread is so old, it’s probably going to have a stroke any minute. ---
**Author:** ![Frazzled](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/frazzled/32/3368_2.png) [@Frazzled](https://boards.straightdope.com/u/Frazzled)\ **Post date:** [October 2, 2013, 8:16pm UTC](https://boards.straightdope.com/t/coumadin-is-rat-poison-really/86722/15 "2013-10-02T20:16:30Z")
dangit - I usually notice Zombie threads… Would Warfarin be effective against zombie Stalin??? I’d pay good money to see a cage match between zombie Stalin and zombie Hitler. Who would win? ---
**Author:** ![Loach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/loach/32/350_2.png) [@Loach](https://boards.straightdope.com/u/Loach)\ **Post date:** [October 2, 2013, 8:25pm UTC](https://boards.straightdope.com/t/coumadin-is-rat-poison-really/86722/16 "2013-10-02T20:25:55Z")
Never trust anything made by John Warfarin at Yoyodyne. ---
**Author:** ![engineer\_comp\_geek](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/engineer_comp_geek/32/504_2.png) [@engineer\_comp\_geek](https://boards.straightdope.com/u/engineer_comp_geek)\ **Post date:** [October 2, 2013, 8:40pm UTC](https://boards.straightdope.com/t/coumadin-is-rat-poison-really/86722/17 "2013-10-02T20:40:10Z")
**Moderator Action** Welcome to the Straight Dope Message Board, inquisitive\_blee. Please note that the thread you are replying to dates back to 2001. We tend to refer to old threads like this that have been revived as zombies (hence, all of the zombie jokes in the replies). While we do permit zombies here, we also ask that you do not revive old threads unless you have new information or something substantial to contribute to the thread. Also, please note that due to this thread’s extreme age, many of its participants may no longer be around to read or comment on your reply. Because of this thread’s extreme age, and because its revival is getting more zombie jokes than actual comments, I am going to put this poor zombie back into his grave. Thread closed.