Cloves are the buds of the Syzygium aromaticum tree, which is native to the Maluku islands located in the eastern part of Indonesia.
They have a sweet, slightly bitter taste and are highly fragrant. Cloves are commonly used as a spice in cooking and baking. They have also been used as a natural remedy in Ayurvedic medicine and Chinese traditional medicines for thousands of years.
Cloves are rich in plant compounds that have been shown to provide powerful anti-inflammatory and antioxidant effects, which is why they are sometimes taken as a dietary supplement.
Though human research is limited, some evidence suggests cloves may offer several health benefits when consumed in high doses. However, clove supplements may interact with certain medications and may not be safe for everyone.
Cloves are most commonly used in cooking and baking, but some people take clove supplements, such as clove extract, clove oil, and ground cloves, in order to promote health.
Human research on the effects of clove supplements is limited, but preliminary studies suggest that cloves may offer a few health benefits due to their high levels of beneficial plant compounds.
High in Antioxidant and Anti-Inflammatory Compounds
Cloves are a rich source of plant compounds that offer antioxidant and anti-inflammatory benefits.
Cloves are particularly high in the compound eugenol, which makes up between 70% to 90% of clove essential oil. Eugenol has been shown to have potent anti-inflammatory, anticancer, antioxidant, and pain-relieving properties.
Findings from animal and test tube studies suggest consuming cloves and clove oil may offer anticancer effects and help protect against inflammation and cellular damage.
For example, rodent studies have shown high doses of cloves could help reduce tumor growth in several types of cancer, including breast cancer.
Rodent studies also suggest cloves offer anti-inflammatory benefits, and may help inhibit inflammatory enzymes, such as Myeloperoxidase (MPO), a marker of inflammation and oxidative stress that’s often elevated in people with certain medical conditions, such as heart disease.
However, while these findings are encouraging, there’s currently no evidence that clove supplements help reduce tumor growth or improve markers of inflammation and cellular damage in humans.
May Help Fight Infections
In traditional medicine systems, cloves were used to treat a variety of infections, including respiratory infections. Studies show cloves offer antifungal, antibacterial, and anti-inflammatory effects, which may be helpful in treating and preventing certain infections.
Clove products, such as clove oil, have been shown to have antifungal and antibacterial effects against pathogens that commonly cause disease in humans, such as Candida yeast and Aspergillus fungus.
Clove mouthwash may help protect against pneumonia infections in certain populations by reducing certain bacteria in the mouth. A recent study included 168 people hospitalized in an Intensive Care Unit (ICU) and on ventilators. The study found the risk of ventilator-associated pneumonia was two times higher in patients treated with a standard mouthwash compared to patients treated with a clove-based mouthwash twice a day for five days.
Other studies have found clove-based oral products may help prevent plaque, gum inflammation, and more.
Additionally, eugenol, the main active compound in cloves, has been shown to prevent viral replication and reduce the viral infection of herpes viruses, such as herpes simplex-1 (HSV-1) and herpes simplex-2 (HSV-2), and offer antiviral effects against hepatitis A and influenza A.
Researchers have also examined whether the compounds found in cloves may be effective in fighting COVID-19 infections. However, human studies are needed to understand if cloves offer any protection against COVID-19 or benefit for people infected with COVID-19.
While animal and test tube studies suggest cloves and clove extract could offer significant protection against certain pathogens and infections, there is currently not enough research for these benefits in humans.
May Reduce Blood Sugar Levels
Limited evidence suggests supplementing with clove extract may help lower blood sugar levels in healthy people and people with prediabetes.
A small study that included 13 people with normal and prediabetic blood sugar readings found supplementing with 250 milligrams (mg) of clove extract per day for 30 days led to significant reductions in post-meal blood sugar levels compared to baseline.
The researchers found clove extract may help decrease blood sugar by reducing glucose production in the liver.
Although these results are encouraging, more research is needed to understand how clove extract may help reduce blood sugar levels.
Clove supplements are available online and in health food stores. However, there’s not enough evidence to make recommendations on how to best take clove supplements.
Clove supplements are available in capsule and liquid form. Some supplements contain only ground cloves or clove extract while other products contain cloves combined with other ingredients.
For example, cloves are sometimes mixed with herbal ingredients, such as oregano. It’s important to check supplement labels for all of the ingredients so know what you’re ingesting.
There’s currently not enough evidence to recommend a safe and effective dose for clove supplements.
However, the World Health Organization (WHO) has set the acceptable intake quantity for cloves as 2.5 mg per kilogram (kg) of bodyweight per day. This means a 130-pound (58.9 kg) person could safely consume around 147 mg of cloves or less per day.
Talk to your healthcare provider about appropriate dosing if you are considering taking clove supplements.
Cloves are safe to ingest in amounts commonly found in foods and used in cooking and baking. The U.S. Food and Drug Administration (FDA) has also recognized clove buds, clove oil, and eugenol as safe.
However, the safety and effectiveness of using cloves supplements in very high doses aren’t well known.
Clove supplements are likely unsafe for infants and children. There have been some reports of children aged three years or younger experiencing serious side effects, such as liver damage, after consuming 5-10 milliliters (mL) of clove oil.
People who are pregnant or breastfeeding women should also not take clove supplements as there is not enough evidence to show clove supplements are safe for these groups.
Clove supplements may interact with several medications, including:
- Blood thinners. Clove supplements may interfere with the body’s ability to clot blood and may increase bleeding risk. For this reason, people taking blood thinners, such as warfarin, should avoid clove supplements. Since cloves may impact bleeding risk, you should also avoid taking clove supplements prior to surgeries.
- Antidiabetic medications. Some research findings suggest clove supplements may reduce blood sugar levels, which may be dangerous for people taking diabetes medications. Taking high-dose clove supplements at the same time as diabetes medications may cause your blood sugar to drop too low, which could be dangerous.
- Other herbs and ingredients. Clove supplements may also interact with other herbs and nutrients known to reduce blood sugar, such as cinnamon, bitter melon, and aloe.
Studies on the safety of clove supplements are limited at this time, and it’s currently unknown if clove supplements have the potential to interact with other medications or other dietary supplements.
If you’re taking one or more medications, consult your healthcare provider before introducing any new supplement into your diet.
What to Look For
If you’d like to take a clove supplement and have talked to your healthcare provider, it’s important to purchase clove products from reputable suppliers.
Whenever possible, purchase clove supplements from companies certified by third-party organizations like U.S. Pharmacopeia and NSF International, which set strict standards for supplement safety and quality.
Clove supplements often contain other ingredients, such as herbs, which may interact with common medications or cause side effects. When shopping for clove supplements, read ingredient labels and avoid products that contain potential allergens or other ingredients that may be unsafe for you to ingest.
This is especially important for people who have allergies to ingredients commonly found in dietary supplements, such as soy, gluten, tree nuts, and dairy.
Can You Take Too Much?
Currently, it’s unknown if high doses of clove supplements are harmful to adults. When taking clove supplements, do not exceed the recommended dosing listed on the supplement label.
Infants and children ages three years and under can experience serious side effects when ingesting more than 5-10 mL of clove oil. For this reason, children should avoid clove supplements.
If you have questions regarding clove supplement dosing, contact your healthcare provider for advice.
Due to the lack of human research on the health effects of clove supplements, their potential side effects are unknown.
In rare cases, infants and children have experienced liver damage, seizure, and other abnormalities after ingesting undiluted clove oil.
Clove oil also contains high amounts of eugenol, which can lead to serious side effects such as seizures and liver injury if very high amounts are ingested. For this reason, clove essential oil should not be ingested.
Though cloves are most commonly used in cooking and baking, they have a long history of medicinal use in traditional medicine systems. Some evidence suggests cloves may offer some health benefits, such as protecting against inflammation, lowering blood sugar levels, and preventing infections caused by certain pathogens.
However, human evidence of the health benefits of clove supplements is limited, and it’s currently unknown how taking large doses of ground cloves or clove extract impacts health. If you’re interested in taking clove-based supplements, it’s important to consult your doctor to ensure safety and appropriate use.