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Dangerous Side Effects of Blood Thinners as Warfarin (Coumadin)

Necrosis caused by warfarin - Coumadin, medicine called it " Necrological manifestation of hematologic disease", altough is side-effect of Warfarin

Necrosis caused by warfarin - Coumadin, medicine called it " Necrological manifestation of hematologic disease", altough is side-effect of Warfarin

Coumadin (Warfarine) controversial blood thinner, that is in use last 60 years

Coumadin (Warfarine) controversial blood thinner, that is in use last 60 years

Bleeding caused by Warfarin - Coumadin, medicine called it " Necrological manifestation of cardiac disease", altough is side-effect of Warfarin

Bleeding caused by Warfarin - Coumadin, medicine called it " Necrological manifestation of cardiac disease", altough is side-effect of Warfarin

Warfarin is today certainly most prescribed blood thinner (anticoagulant), that has very interesting and controversial dual use: while people take it for thinning the blood, it is also used as a rat poison since the day of it`s invention.. So, when warfarin had been invented, and successfully "tested" on rats (rats are successfully dying from it) pharmacy industry, at the same time, started to produce the very same medication for humans. with the completely same ingredients.

Warfarin is sold as: Coumadin, Jantoven, Marevan, Lawarin, and Waran

History of warfarin explains a lot:

Main active substance in warfarin (dicoumarol), is derived by various rotten plants but only if they are in process of degradation attacked by certain group of fungus in addition to the presence of toxic gas formaldehyde (that can be realised when urea is added, or some formaldehyde chemicals). This substance was discovered in 1940s, when was observed that after eating such spoiled and toxic meal (grass) on one farm in Wisconsin , cattle died from heavy internal bleeding (hemorrhage). American biochemist, Karl Paul Gerhart Link, managed to copy this process that unluckily occurred after the rotten and poisoned meal was given to the cows, and warfarin started to be produced as rat poison. Rats poisoned with anticoagulants die from internal bleeding, due to the loss of the blood´s clotting ability and damage to the capillaries. Prior to death, the animal exhibits increasing weakness due to blood loss, though appetite and body weight are not specifically affected. Because warfarin is slow in action (several days following the ingestion of a lethal dose), the target animal is unable to associate the illness with the bait eaten e.g rats needed some time to find connection and started to avoid warfarin baits.

This inventive poison pharmacist started to produce for human needs after they discovered that people would not necessarily immediately die after consumption of warfarin, what they learned in 1951, when an US army soldier unsuccessfully attempted suicide with multiple doses of warfarin and recovered fully in hospital, after being treated with vitamin K (vitamin K is antidote for warfarin).

Survival of US army soldier inspired pharmacy industry to use the rat poison as blood thinner for very many health conditions when thinning the blood would be beneficial, despite very many side effects mentioned poison can have (warfarin can cause dead). The warfarin was approved for human use as blood thinner in 1954.


Dwight Eisenhower -  Side-effects of  Coumadin

Dwight Eisenhower - Side-effects of Coumadin

President Dwight Eisenhower Suffered from Side-effects Of Warfarin

Warfarine with trade name Coumadin was popularized when USA president Eisenhower started to use it in 1955, after his heart attack. While he was still on Warfarin, he got chronic inflammation of intestines because of Warfarin poisoning in 1956. His medical condition was seriously in danger, even bowel surgery perfromed, so his Warfarin (Coumadin) therapy was temporarly suspended by his doctors. After he recovered, he again started to take warfarin (Coumadin) what led him to the brain hemmorhage (stroke) in 1957- and finally to serial of heart attacks that led to his death in 1969.

Ironically, in spite of deadly "side-effects" Mr Eisenhower experienced from using warfarin, marketing of pharmaceutical industry made it to become the second popular and worldwide prescribed blood thinner .


Rats More Cautious About Warfarin Than Humans

In the meantime, rats learned to connect their bleeding disease with warfarin enhanced "food" . They are extremely intelligent, and always send one member of their community to test suspicious bait, then they wait for days before all members of the group decide to eat such food. If the rat who tested it survives, food is safe for the whole group. If it develops health problems, in the following days, nobody else eats it. Due to rats` intelligence ( who seem to be far more cautios with warfarin then humans ), warfarin became much less effective in rats` population control then it was before, so chemists needed to invented new poison with prolonged effect that starts to cause deadly bleeding much later then warfarin used to (super-warfarin). Of course, scientists could not admit that rats are so intelligent, and more cautious then people, so they publicly announced that rats developed Warfarin - resistance, while they simply learned how to avoid mass poisoning.

Luckily for the people, super-warfarin is still not used in human medicine, but Warfarin is still normally prescribed medicine, warmly recommended from many pharmacists and doctors.

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How Warfarin Works

It`s main duty is to surpress production of vitamin K in the body.

Vitamin K is responsible for clotting the blood, that is needed to stop any kind of bleeding one could experience. Problem arise only if clotts are formed on the wrong place - in veins and arteries, when blood is too thick.

Vitamin K is also antidot for dangerous side-effects of Warfarin medication, one can find it naturally: .in broccoli, kale, spinach, green leafy vegetables, chickpeas, soybean products, green tea, beef liver and pork liver.


Warfarin interacts with various herbs and spices, some used in food (such as ginger and garlic) and others used for medicinal purposes ( ginseng and Ginkgo biloba). All may increase bleeding and brusing in people taking warfarin; similar effects have been reported with borage (starflower) oil or fish oils. .

Some antibiotics,(as Acetominophen and Ibuprophen), Aspirin, (and various other medicines) garlic and garlic supplements, cranberry supplements, cranberries or cranberry juice, alcohol, licorice and vegetable oils are also thinning the blood, so one should strictly avoid them while using warfarin-

Side effects of Warfarin

Longterm or Delayed Health Effects

  • Prolonged warfarin use may cause cancer and can harm brain and central nervous system
  • Multiple birth defects including bone and nasal deformities, blindness or unusually small eyes, hydrocephalus (water on the brain), mental retardation.
  • Fetal, neonatal or maternal bleeding.
  • Bleeding from the nose, lip, gums or upper airway, blood in urine and feces, bruising, rash.
  • Paleness or fatigue caused by anemia, muscle and joint pain, blurry vision, eye pain.
  • Vomiting, abdominal pain, diarrhea.
  • Upper airway pain, difficulty in speaking and swallowing, shortness of breath.
  • increases coronary calcifications in man,
  • worsens hypertension in high-risk patients, particularly in those with diabetes mellitus (studies about it shown below the comments.)


Pharmacists are also developing new types of blood thinners with prolonged acting, and also some new blood thiners, much more expensive then Warfarin /Coumadin (as Pradaxa, that costs over 200 $ US, but has completely similar side effects as Warfarin and Heparin. The difference is only in price. As usual, pharmacy industry cares only about profit.

Natural Blood Thinners

Nature always work the best in the long term, and is the safe way to prevent the excessive blood clotting, without any of above mentioned side-effets:
Garlic and garlic supplements, onion, onion,,ginko biloba, dong quai, feverfew, fish oil, vitamin E, are a few of many known natural blood thinners.

It is also important that one drinks sufficient amount of liquids during the day (water is the best), and also avoid the food that consists a lot of vitamin K - as broccoli, kale, spinach, green leafy vegetables, chickpeas, soybean products, green tea, beef liver and pork liver. Healthy and balanced diet is also very important.

I believe that after reading my article, your choice about type of blood thinner is clear - I would always vote for natural ways.


Tatiana Michaela Pribic

Homeopath and Reiki Teacher.

Studies about harmfull effect of Warfarin

Effects of warfarin on blood pressure in men with diabetes and hypertension - a longitudinal study.

Department of Medicine, University of Connecticut School of Medicine, Farmington, CT, USA .J Clin Hypertens (Greenwich). 2007 Apr;9(4):256-8.


Warfarin causes extensive vascular calcification leading to increased systolic blood pressure and pulse pressure in rats, may be associated with increased valvular and coronary calcifications in man, and possibly worsens hypertension in high-risk patients, particularly in those with diabetes mellitus or uncontrolled hypertension. The authors evaluated blood pressure and intensity of antihypertensive therapy over 36 months in a cohort of 58 patients with diabetes and hypertension on warfarin and 58 control subjects with diabetes and hypertension not on warfarin. The results demonstrate that warfarin therapy at conventional  does increase systolic blood pressure or pulse pressure in patients with diabetes and hypertension.


Warfarin and aortic valve calcification in hemodialysis patients.

Division of Nephrology, Queen's University, Kingston, Ontario, Canada. J Nephrol. 2007 Jul-Aug;20(4):417-22.

BACKGROUND: This retrospective cohort study was designed to determine the association between long-term exposure to warfarin and severity of aortic valve (AV) calcification in hemodialysis (HD) patients.

METHODS: 108 HD patients underwent a study-specific echocardiogram. A grading scheme was used to classify AV calcification as none, mild, moderate and severe.

RESULTS: One hundred and eight subjects were enrolled. A minority had no calcification (n=17, 15.7%), the majority had mild calcification (n=62, 57.4%), and fewer had calcification rated as moderate (n=16, 14.8%) or severe (n=13, 12%). Dialysis vintage was associated with severity of AV calcification (p=0.04). The 18 subjects with long-term warfarin exposure (36.7 +/- 19.7 months) were more likely to have severe AV calcification (p=0.04). The odds ratio of falling into a higher category of AV calcification following 18 months of warfarin was 3.77 (95% confidence ratio, 0.97-14.70; p=0.055). There was an association between lifetime months of warfarin exposure and severity of AV calcification (p=0.004) that was independent of dialysis vintage, calcium and calcitriol intake.

CONCLUSIONS: The data suggest that warfarin may be associated with severity of aortic valve calcification in HD patients and support the need for prospective studies.


Tammy Winters from Oregon on October 15, 2020:

Interesting article. Thanks for sharing.

Martin Eesti on December 04, 2014:

My neighbor, a non-drinker & non-smoker, developed an irregular, thumping heartbeat. His doctor put him on warfarin and a beta blocker. Five years later he got liver cancer, which caused his death. I suspect side effects from the drugs caused the cancer.

Martin Eesti on December 04, 2014:

My dad was on warfarin and a beta blocker OR calcium blocker for about seven years. He developed cancer that was burned off by radiation. He died of congestive heart failure, after a couple of heart attacks. Nutritional cures, I think, would've cured him

Beth on August 29, 2014:

My dad has been taking Coumadin for several years. Just recently he was very anemic and weak. They found a bleeding ulcer, took a biopsy, it was ok. Check up did another scope and a biopsy ... cancer!! I have never liked this Coumadin... now I HATE it!!!

Thank you for this info. (Tears)

Martin Eesti on June 11, 2014:

What an eye opener, to learn that Warfarin makes atherosclerosis (calcified arteries) even worse, by causing MORE plaque. I'm switching to health food stores' natural SERRAPEPTASE, which dissolves this plaque. Good reading about it at The site will email you a free 33page book about it.

karen1975 on March 06, 2014:

I have been on wafarin for 4 years now after 2 massive dvt's 7 months apart.My inr is monitored roughly 3 weekly.That is until last week when my inr had dropped to 1.2 on thursday.I had a terrible headache and sentitivity to light that had started wednesday night.saturday I woke up feeling like I was drunk and my arm was numb. I was put in hospital as they thought I'd had a stroke and my inr had dropped to 1.1.Hospital have now put me on 10mg daily now, inr today is 2.1 and my pain is feeling a little duller today but still feel very light headed and light sensitive aswell as my left arm been very cold.They now think I suffer from Hemiplegic migraines maybe brought on when my levels drop.I am also very tired and no energy could this be due to the warfarin?

Funom Theophilus Makama from Europe on February 21, 2014:

Cannot agree more! What an excellent piece you have here

Ireno Alcala from Bicol, Philippines on September 13, 2013:

This is a timely information that should never be taken for granted. Thanks for sharing, Ms. T!

john on July 01, 2013:

this was 2 days aggo

john on July 01, 2013:

i took 300mg of cumidin should i b ok now?

AL on May 26, 2013:


Would it be possible to find out your resources for this information? I'm very interested in this subject, as my mother now has liver cancer and I'm doing my own unofficial research. Thank you for this article.

Surjit Grewal on January 02, 2013:

I have been taking warfarine for the last 5 years-- have short of breath, feel tired very easily, but I have Asthama + over weight, 67 years old.Taking Digoxin and bisoprolol for the safety of heart-never in my life I have blood Pressure+ heart beat is always around 62. Sure I have gained weight. Short of breath is main problem.Moderation of green vegetabels-use it.

Azel Hill Beckner from Bowling Green, Kentucky on November 08, 2012:

Bowling Green,KY /Warren County Health Department disstributed Warfarin rat poison to be used as a blood thinner. My parents used it and died from strokes.

Cathy Nerujen from Edge of Reality and Known Space on January 24, 2012:

Oh wow, rat poison. Geez, I think someone I know who takes that stuff. That is bizarre. I learned some new things here in your hub. Thank you for sharing this.

Superjonesable from Knoxville, TN on January 01, 2012:

While I agree that blood thinners such as Warfarin are overused in today's pill minded society I must say that at least a third or more people that are on it would not do well on things like garlic or other natural supplements. I say this because blood thinning medications are given to individuals with conditions that could be deadly if not given proper treatment.

Yes warfarin is used as a poison, but so could distilled water. I can show you that one drop of distilled water on a slide with blood on it will cause ALL the red blood cells to pop. This would certainly be something alarming but makes you think, could this be dangerous. Yes it could kill you but the likelyhood of drinking so much distilled water to dilute your blood electrolytes are so low that it shouldn't be an issue. Same for warfarin.

If the levels are monitored and the intake of foods high in vitamin K are watched as well then life should continue.

ONE issue I do have with anticoagulants would be that they can cause damage to liver tissue with use over time and can therefore cause the liver to be unable to regulate clotting the way it should.

I am glad that warfarin is on the market but I wouldn't take it unless I was sure I needed it.


Debby Bruck on August 08, 2011:

Dear Tatjana ~ Always the best hubs around. I like your new profile photo. Love and light, Debby

Pollyannalana from US on July 03, 2011:

I had no idea how dangerous this medicine was although I took my mother every 2 weeks for testing and it caused a tumor on her brain and four years of hell on earth for her and me. She past away last June a year ago. It is a great thing to warn people about. She could not have vitamin K or cabbage or too many greens, makes sense now.

rihsam10 on May 11, 2011:

fantastic hub. thank you for sharing this information

Hello, hello, from London, UK on May 11, 2011:

A well written and detailed hub. You cdertainly gave a lot of ideas. Very interesting about the rats. I never knew.

Tatjana-Mihaela (author) from Zadar, CROATIA on May 10, 2011:

Thank you Mary for your comment, a lots of hugs and love to you - always.

Tatjana-Mihaela (author) from Zadar, CROATIA on May 09, 2011:

Thank you very much Jason Hill for the nice words - you cannot be more right, I do write because of passion, for sure.

Craig Suits from Florida on May 09, 2011:

Hiya T...

Great informative hub and great pics too (AS USUAL). I never heard that was Eisenhowers problem before. Where the hell do you get all these diverce subjects from? You should be thinking about getting an official degree at the end of your name. Oh something simple (for you) like maybe a "PHD". I know you don't care much about things like that but your credibility would skyrocket along with your ability to share, educate, and even heal. Think about it. "DR.T" sounds pretty cool too.

Is it possible to be very very proud of someone on the other side of the world? Someone you've never met and someone you hardly even know?

Yup...It is...

Take care little girl. Your the best of the best....

Vinod from Hyderabad, India on May 08, 2011:

Thank you Tatjana for an interesting hub with some very useful information.

Richard Parr from Australia on May 07, 2011:

My work puts me in touch with many elderly folk who use warfarin. From the things they have shared with me, you have presented its side-effects very accurately. One of the issues with thinning blood is that it will also reduce the volume of oxygen and nutrients that can be carried by the blood; therefore considerably more blood is required to service the body than normal. It's a catch 22. Any means that naturally improves circulation should be preferred.

Tatjana-Mihaela (author) from Zadar, CROATIA on May 07, 2011:

Thank you very much, gis...

Martie Coetser from South Africa on May 07, 2011:

Excellent hub about Warfarin and natural blood-thinners. We should in fact realise that ALL medicine are toxicants. Take care!

Tatjana-Mihaela (author) from Zadar, CROATIA on May 07, 2011:

Thank you so much Happyboomernurse for your valuable observation from your own experience as a nurse. Your comment is highly appreciated.

Tatjana-Mihaela (author) from Zadar, CROATIA on May 07, 2011:

Thank you very much Ralph for your comment, take care about yourself.

Susan Hazelton from Northern New York on May 07, 2011:

You have to be so careful with blood thinners. Thank you for the complete list of side effects.

Petra Vlah from Los Angeles on May 06, 2011:

As usual, this is a very informative hub with much needed information. After his heart attack my husband was given fatal doses of blood thinners and now that I learned from you how dangerous they are I can understand better the damage they caused.

VioletSun from Oregon/ Name: Marie on May 06, 2011:

I had no idea that the ingredients used in rat poison is used in Warfarin. Yikes!!! Sad to see the medication actually contribute to the death of President Eisenhower and countless of other patients, I am sure.

Very informative article and rated up!

Hugs and love~

Spiritual.Space from USA on May 06, 2011:

Great article. More people should be aware of the pharmaceutical companies and that the drugs aren't so glamorous.

Jason Hill on May 06, 2011:

One of the best hubs I have seen in a while! This was well written with tons of useful information. I love the photos and the fact that there is no promotion of useless products. It shows that you are here to write for the passion of writing and not to try and make a quick buck!

gis_r07 from Boston, MA on May 06, 2011:

Great article. I know someone who is presently experiencing some of the aforementioned side effects, having taken Coumadin for an extended period of time. Voted up and useful. Thank you.

Gail Sobotkin from South Carolina on May 06, 2011:

This was quite a shocking article, and I had no idea of the history of warfarin's development. I did, however,(before my retirement) take care of many patients on coumadin and frequent blood test monitoring was necessary to try to avoid the side effects you mentioned. Even so, some patients still developed serious side effects. Yet the medical establishment and medical literature claimed, and continues to claim that when prescribed by a doctor, and carefully monitored, the benefit exceeds the risk of side effects for some patients.

Ralph Deeds from Birmingham, Michigan on May 06, 2011:

Good information. (I've been taking warfarin for a couple or three years. Getting the correct dosage is difficult. I have to get a blood test once a month or so.)

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