Natural blood thinners are substances that reduce the blood’s ability to form clots. Blood clotting is a necessary process, but sometimes the blood can clot too much, leading to complications that can be potentially dangerous.

People who have certain medical conditions, such as congenital heart defects, may require blood-thinning medications to reduce their risk of heart attack or stroke.

Blood thinners work in two ways. Antiplatelets keep blood cells from sticking together to become a clot. Anticoagulants cause clotting to occur more slowly.

It is essential to speak with a doctor before trying natural remedies, as they may not work as well as medication and may interfere with some prescription drugs.

Some foods and other substances that may act as natural blood thinners and help reduce the risk of clots include the following:

blood-thinning spices scattered around a mortar and pestleShare on Pinterest
Rowan Jordan/Getty Images

People have long used the golden spice known as turmeric for culinary and medicinal purposes. Curcumin is an active ingredient in turmeric and appears to have anti-inflammatory and blood-thinning or anticoagulant properties.

A 2019 review in the EPMA Journal indicates that turmeric may help block blood clotting and advises caution when combining turmeric with blood-thinning drugs.

People can add turmeric to curries and soups, or mix it with hot water to make a comforting tea.

Ginger is another anti-inflammatory spice that may stop blood clotting. It contains a natural acid called salicylate. Aspirin, also known as acetylsalicylic acid, is a synthetic derivative of salicylate and a potent blood thinner.

To get the anticoagulant effects of natural salicylates, people may want to use fresh or dried ginger regularly in baking, cooking, and juices.

It is unlikely, however, that natural salicylates are as effective as blood-thinning medications.

A 2015 literature review of 10 studies also suggests that ginger’s effects on blood clotting are unclear. It indicates that more research is needed to fully understand the potential blood-thinning properties of ginger.

Cayenne peppers are also high in salicylates and may act as powerful blood-thinning agents.

A 2019 study in the Ascendens Asia Journal of Multidisciplinary Research finds that cayenne pepper extract slowed blood clotting in type O+ blood samples.

Cayenne pepper is quite spicy, however, and many people can only tolerate it in small amounts.

Capsules containing cayenne pepper are available in health food stores and online. Other benefits of this spice may include:

Vitamin E reduces blood clotting in a few different ways. These effects depend on the amount of vitamin E that a person takes.

The National Institutes of Health’s Office of Dietary Supplements suggests that people who are taking blood-thinning drugs should avoid taking large doses of vitamin E.

It is unclear how much vitamin E thins the blood, although it is likely that people would need to take more than 400 international units (IU) per day.

Taking high doses of vitamin E supplements, for example, above 1,500 IU daily, on a long-term basis may have negative effects.

It may be safer to get vitamin E from foods rather than supplements. Foods that contain vitamin E include:

  • almonds
  • safflower oil
  • sunflower oil
  • sunflower seeds
  • spinach
  • peanut butter
  • whole grains

Besides its often desirable taste in food and cooking, garlic has natural antibiotic and antimicrobial properties.

A 2018 study from Food Science and Biotechnology reports that garlic powder demonstrates antithrombotic activities in rats. An antithrombotic agent is a substance that reduces blood clot formation.

A 2020 review of studies found that garlic supplements helped reduce blood pressure and had mild antithrombotic effects.

Research from 2015 in Medicines notes that since dietary supplements, including garlic, may affect platelet function and coagulation, it is best to avoid them before surgery.

Cinnamon contains coumarin, a powerful blood-thinning agent. Warfarin, a commonly used blood-thinning drug, is derived from coumarin.

Chinese cassia cinnamon contains a much higher coumarin content than Ceylon cinnamon, according to a 2012 study in Pharmacognosy Research. However, taking coumarin-rich cinnamon on a long-term basis can cause liver damage.

It may be best to stick to small amounts of cinnamon in the diet in addition to using other natural blood thinners.

Practitioners of traditional Chinese medicine have used leaves from the Ginkgo biloba tree for thousands of years. Ginkgo is also a very popular herbal supplement in the United States and Europe. People take it for blood disorders and memory problems.

According to one 2019 study in Bioorganic Chemistry, several compounds in Ginkgo biloba may block thrombin, an enzyme that causes blood clotting.

However, researchers carried out the study in a laboratory, rather than on people or animals. Further research is necessary to see if ginkgo has the same effects on the human body.

There is some evidence to suggest that grape seed extract may have potential benefits for several heart and blood conditions.

It may also help prevent high blood pressure, though the research is mixed.

Grape seed extract may also act as a natural blood thinner. Because of these effects, the National Center for Complementary and Integrative Health suggests that certain groups of people should not take grape seed extract, including people:

  • with blood disorders
  • who take blood-thinning medications
  • who are about to have an operation

Dong quai, also known as “female ginseng,” is another traditional Chinese herb that may reduce blood clotting.

This effect may result from dong quai’s coumarin content, the same substance that makes cinnamon such a potent anticoagulant.

However, a small study from 2015 in Blood finds that taking 1,000 milligrams (mg) of dong quai daily did not significantly affect blood clotting. The authors note that additional research is needed.

People take dong quai orally and can consume it in herbal tea or soup.

Feverfew is a medicinal herb that comes from the same family as daisies, or the Asteraceae family. People may take feverfew for:

According to one case report in Journal of Medical Cases, taking feverfew was followed by vaginal bleeding and a longer menstrual cycle. After stopping feverfew, the person’s blood coagulation returned to normal. The report’s authors cautioned against taking feverfew before surgery or with blood-thinning drugs.

Still, studies are needed in large groups of people to confirm these effects.

Feverfew is available in capsule or liquid form.

Bromelain is an enzyme that is extracted from pineapples. It may have anti-inflammatory properties and might be an effective remedy for cardiovascular diseases.

One 2016 study from Blood Coagulation & Fibrinolysis found that bromelain added to in vitro blood samples increased the time the blood took to clot, or its prothrombin time. However, injecting bromelain into a small number of mice did not show this effect, and more research needs to be done.

Bromelain is available in supplement form from health stores and drugstores.

Aloe has been used for hundreds of years, both topically and as a dietary supplement. People take it to help with conditions including:

Like ginger and cayenne pepper, aloe contains salicylates that likely cause blood-thinning effects.

One 2020 study in The Professional Medical Journal found that, when added to blood in a laboratory, aloe vera gel demonstrated an antiplatelet effect similar to aspirin. However, more research is needed on aloe as a dietary supplement in humans.

People can take aloe as a capsule or as a soft gel. Because of its potential effects on bleeding, people should stop taking aloe at least 2 weeks before having surgery.

Oil from evening primrose, or Oenothera biennis, may help with:

In fact, evening primrose was known as the “King’s cure-all” in Europe in the 1600s.

Evening primrose oil may also reduce blood clotting. A 2020 case study in Cureus reported that one woman’s thrombocytopenia, a condition in which there is a low number of platelets in the blood, was likely worsened by her taking black seed oil and evening primrose oil.

Research from 2017 in mice also indicates that taking evening primrose oil may help prevent drug-induced thrombosis, a dangerous condition in which blood clots form within veins.

However, more research in large groups of people is required to evaluate the supplement’s safety and effectiveness for health conditions.

Melatonin is a hormone that the body produces to regulate the circadian rhythm. Some people also take melatonin as a supplement to help with sleep and sleep disorders.

Studies suggest that melatonin likely affects blood clotting. One 2020 research review from Diabetes and Vascular Disease Research indicates that melatonin may block the clumping of platelets to form clots.

A study from 2017 in Journal of Pineal Research also finds that melatonin inhibits platelet activation, a process that leads to clots.

Melatonin may cause a higher risk of bleeding if a person takes it with warfarin (Coumadin). It may also interact with other medications. As with any supplement, it is important to talk with a doctor before taking melatonin.

Many natural substances may reduce clotting to some degree. But natural remedies are unlikely to be as effective as blood-thinning drugs, and people at risk of blood clots should not use them instead of prescription medications.

Government authorities do not monitor herbs and supplements as closely as food and drugs. People should research different brands carefully before buying to ensure that the products are of high quality.

People taking prescription blood thinners should not use natural remedies without talking with their doctor first.

Even though they are natural, some substances and foods may thin the blood too much, especially when people take them in conjunction with medications. This can increase the risk of bleeding.

People can usually consume foods with potential blood-thinning properties safely in reasonable amounts. However, it is essential to speak with a doctor before trying herbal remedies such as dong quai and grape seed extract.

Note that people should not take some of these products alongside blood-thinning medications.

Read this article in Spanish.