Updated on August 21, 2023
4 min read

Alcohol and Blood: How, Why, and the Duration of Effects

Alcohol can thin your blood by preventing cells from sticking together and creating clots. This may reduce the risk of strokes from blood vessel blockages but increase the risk of hemorrhagic strokes.

A hemorrhagic stroke is a form of brain damage caused by bleeding in the brain. The risk of a hemorrhagic stroke increases if you drink large quantities of alcohol.7

How Does Alcohol Thin Your Blood?

Alcohol may help prevent blood clotting by reducing blood cells called platelets. It does this by interfering with the blood cell production in the bone marrow, making them sticky.

Clotting is necessary and beneficial and necessary when you’re injured. Platelets move to the injury site and clump together to close the wound.

However, sometimes a blood clot can form in or move to an artery that provides your heart or brain with oxygen. When a clot stops blood flow to your heart, it can lead to a heart attack. If a clot blocks the blood flow to your brain, it can result in a stroke.

How Much Alcohol Does it Take to Thin Your Blood?

Drinking more than three alcoholic beverages daily could impact blood cell production and increase your risk for hemorrhagic strokes. However, drinking a glass or two of wine daily may reduce your risk for heart disease and strokes resulting from blood vessel blockage (ischemic strokes).4


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How Long Does Alcohol Affect Blood?

Alcohol stays in your blood for up to 12 hours. However, the effects of alcohol on platelets are short if you drink moderately. If you drink too much alcohol, it can have adverse side effects. 

These side effects include:

  • Excessive blood thinning
  • Increased blood pressure
  • Increased risk of heart problems
  • Increased risk of bleeding

Long-Term Side Effects of Alcohol on Your Blood

Having more than three drinks in one sitting temporarily raises blood pressure. Repeated binge drinking can lead to a long-term increase in blood pressure.

Heavy drinkers can have rebound health effects in which the bleeding risk increases even after they’ve stopped drinking. Exceeding 15 drinks a week for men or 8 for women is considered heavy drinking.8

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Can You Drink Alcohol While Taking Blood Thinners?

Alcohol will interact with blood thinners like Coumadin (warfarin), increasing the medication’s anticoagulant effect and your risk of bleeding2. You should avoid or reduce the amount of alcohol you drink while on blood thinners.

Alcohol might also reduce the rate your body breaks down and removes the blood-thinning drug. This can cause a dangerous buildup of the drug in your body.

If you drink alcohol, healthcare providers might have difficulty giving you the correct dosage for prescribed blood thinners. Ask your doctor if it’s safe to drink while on blood thinners.

Risks of Drinking Alcohol While on Blood Thinners

Blood thinners and alcohol can interact with other prescriptions you take. Make sure to follow the precautions on blood thinners and avoid drinking alcohol.

Thin blood from disrupted clotting can increase the risk of excessive bleeding. This can be dangerous for minor wounds or during surgery. When this occurs, the blood can’t clot properly, increasing the risk of blood loss.

If your doctor prescribes a drug like Coumadin, you’ll also have your blood tested to ensure you get the correct amount of blood thinning. If there’s not enough thinning, you aren’t protected. But if there’s too much, you risk bleeding.3

Can You Drink Alcohol Instead of Blood Thinners?

No, you shouldn’t use alcohol as a substitute for blood thinners. Blood thinners help prevent clotting, which can lead to heart attacks or strokes. 

If your doctor has prescribed blood thinners, you’re likely at risk for heart disease or a blood clot. Drinking alcohol can worsen your condition.2

Drinking alcohol as a blood thinner can put you at greater risk for:

  • A bleeding stroke
  • Liver disease
  • Mental health issues
  • Stomach bleeding or ulcers
  • Alcohol dependence or addiction 

How to Thicken Your Blood if Alcohol Has Thinned It

Your doctor may prescribe you blood-thickening medication. You can also naturally thicken your blood by eating certain foods.

Consider eating foods high in vitamin K. This fat-soluble nutrient is ideal for thickening or clotting blood. It’s sometimes known as the ‘clotting vitamin’ for its essential role in blood coagulation. 

Vitamin K is produced in the body by bacteria in the gastrointestinal tract. It’s also found naturally in many vegetables, including:

  • One cup of raw brussels sprouts contains around 156 micrograms
  • One cup of raw broccoli contains about 93 micrograms
  • One cup of raw cabbage contains approximately 67 micrograms

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Alcohol can thin your blood. It prevents your blood cells from sticking together and reduces platelets. 

You should avoid mixing alcohol with blood thinners because it can increase the drug's anticoagulant effect. This can cause excessive bleeding and increase the risk of heart problems.

If alcohol has thinned your blood, your doctor can prescribe blood-thickening medication. Certain foods can also thicken your blood, including meals containing vitamin K.

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Updated on August 21, 2023
8 sources cited
Updated on August 21, 2023
  1. 2015-2020 Dietary Guidelines, U.S. Department of Health and Human Services, 2021. 
  2. Roth et al. “Alcohol misuse, genetics, and major bleeding among warfarin therapy patients in a community setting.” Pharmacoepidemiology and Drug Safety, 2015.
  3. Diagnosis and Treatment of Venous Thromboembolism, Centers for Disease Control and Prevention (CDC), 2020.
  4. Dimmitt, SB et al. “The effects of alcohol on coagulation and fibrinolytic factors: a controlled trial.” Blood coagulation & fibrinolysis: an international journal in hemostasis and thrombosis, 1998.
  5. Eismann et al. “Influence of alcohol consumption on blood coagulation in rotational thromboelastometry (ROTEM): an in-vivo study.” Korean journal of anesthesiology, 2020.
  6. Olsen, H. “Effects of ethanol on human blood fibrinolysis and coagulation.” Alcohol and alcoholism (Oxford, Oxfordshire). Supplement, 1987.
  7. Unnithan et al. “Hemorrhagic Stroke.” StatPearls, Treasure Island (FL), 2022.
  8. Excessive Alcohol Use.” Centers for Disease Control and Prevention, 2022.

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