Oregano Oil: 6 Major Side Effects You Must Know

Consuming too much of this fragrant oil may cause more pain than gain.

Medically reviewed by Serena Benali, RDN Serena Benali Serena BenaliRDN linkedin_icon
Written by , BSc, Professional Certificate in Food, Nutrition and Health Ravi Teja Tadimalla BSc, Professional Certificate in Food, Nutrition and Health linkedin_icon Experience: 8 years
Edited by , BA (Literature & Psychology), PG Diploma Arshiya Syeda BA (Literature & Psychology), PG Diploma linkedin_icon Experience: 7 years
Fact-checked by , BEd, MSc (Microbiology), Diploma In Nutrition Aparna Mallampalli BEd, MSc (Microbiology), Diploma In Nutrition linkedin_icon Experience: 5 years

The side effects of oregano oil may make you reconsider using it. It is an essential oil extracted from the Italian herb oregano. While the herb is commonly used in various recipes, the essential oil is renowned for its antimicrobial qualities (1).

Oregano oil contains several beneficial chemical compounds. However, when taken in excess, it can produce some unpleasant side effects. This article examines the side effects of oregano oil and potential drug interactions. Read on.

protip_icon Know The Flip Side: Oregano Oil

Short-Term Effects
Skin irritation, nausea, vomiting, diarrhea, and lower blood sugar levels.

Long-Term Effects
May induce abortion and lead to cardiac and respiratory damage.

Drug Interactions
It may interact with diabetes medications and hinder the absorption of zinc, iron, and copper.

When To See A Doctor
In case of rashes, stomach distress, difficulty swallowing, muscle pain, and vaginal bleeding (if you are pregnant), consult a physician.

What Are The Side Effects Of Oregano Oil?

Woman experiences skin irritation as a side effect of using oregano oil
Image: Shutterstock

Oregano oil may cause skin allergies in certain individuals. It may also lead to gastric distress and hypoglycemiai  A condition in which your blood sugar levels are lower than the standard range and cause anxiety and heart palpitations. . Some reports suggest that the oil can also cause miscarriage and must be avoided by pregnant women.

1. May Cause Skin Irritation

Though oregano oil is usually well-tolerated, it can cause skin allergies in certain individuals (2). These effects could be more pronounced in oregano oil supplements as such products do not require strict approvals by the US FDA (Food and Drug Administration).

Individuals allergic to plants in the Lamiaceae family tend to show allergic reactions to oregano as well. The other plants in this family include basil, marjoram, sage, mint, and lavender (3).

In some people, oregano oil can also cause skin irritation in concentrations as low as 3-5%. Inhaling the oil may not have such effects (4).

Chrissy, a YouTuber, shared her experience of using oregano oil to manage acne. She said, “I had a couple of, you know, cystic pimples on my chin…and the oregano oil gave me a chemical burn (i).” She warned against using essential oils without prior research and guidance and adding, “It took exactly 5-6 days to completely peel off, and one word of caution is do not peel this yourself because it is something that needs to heal on its own and it will peel when it’s ripe.”

2. May Cause Gastric Distress

Woman experiences gastric distress as a side effect of using oregano oil
Image: Shutterstock

Although rare, intake of oregano oil may lead to gastrointestinal distressi  A group of digestive disorders that cause symptoms like abdominal discomfort, nausea, and bloating. like nausea, vomiting, and diarrhea (2). However, there is very limited research as to why that occurs. Hence, please consult your doctor before ingesting the oil.

3. May Lead To Hypoglycemia

Carvacrol, a strong antioxidant compound in oregano oil, could be responsible for its ability to reduce blood glucose levels, which can cause dizziness in some. In an animal study, it was found to show reductions in blood glucose levels (5). Though this could be good news, individuals who are already on medications to lower blood sugar must consult a doctor before consuming oregano oil or its supplements.

Oregano oil may also be one of the few essential oils that can impact glucose sensitivity (6). If you are already on diabetes medications, oregano oil may further accentuate the effects.

4. May Have Abortifacient Effects

Oregano oil may cause miscarriage
Image: Shutterstock

A herbal infusion containing oregano was reported to induce abortions in pregnant women (7). The herbal infusion contains various other herbs in large amounts.

Many anecdotal evidence suggests that herbal infusions may cause miscarriage. Termed the herbal abortion, it is a process involving the consumption of a series of herbs to induce a miscarriage deliberately (8). Oregano oil may be one such herb.

There is less research directly linking oregano oil to miscarriage. However, please exercise caution as the oil may have abortifacienti  A substance, medication, or herbal concoction used by healers for centuries to terminate a pregnancy. effects (9).

protip_icon Quick Tip
Oregano essential may help prevent cancer. It fights against genotoxic agents, which can alter the DNA and may cause cancer or mutation (11).

5. May Lead To Cardiac And Respiratory Collapse

Oregano contains another compound, thymoli  A white crystalline substance present in thyme and oregano oil which may cause respiratory and cardiac collapse. , which may lead to cardiac and respiratory collapse. The compound may also lead to central hyperactivity, convulsions, and even coma. Though these effects are rare, it is important you be aware of them (10).

6. May Interact With Certain Drugs

Oregano oil may interact with diabetes medication
Image: Shutterstock

Given its hypoglycemic effects, oregano oil might interact with diabetes medications. There is no research to support this, though. If you are taking diabetes medications, please check with your doctor before you consume oregano oil.

Anecdotal evidence suggests that oregano oil may also interfere with blood-thinning medications, the absorption of zinc, iron, and copper. Those taking these supplements must consult their doctor before ingesting oregano oil. There is very little research to support this.

protip_icon Quick Tip
Taking oregano oil with diabetes medications may cause drug-herb interaction and lead to extremely low blood sugar levels.

Now that you know about the side effects of oregano oil, how is it different from oil of oregano? Find out in the next section.

Oil Of Oregano VS. Oregano Essential Oil

Oil of oregano and oregano essential oil are two types of oregano oils. The former is extracted from the leaves and flowering tops of the oregano plant and is available in the form of capsules or a liquid. Oregano essential oil, on the other hand, is a concentrated extract of the oregano plant that is often used in aromatherapy. While there is limited research on both products, anecdotal evidence suggests that excess use of both products may cause dizziness, vomiting, or an allergic reaction. Hence, ensure that you purchase from a reputed brand and do a patch test before use.

What Is The Ideal Dosage Of Oregano Oil?

Woman pouring a few drops of oregano oil into a bowl
Image: Shutterstock

There is little information available about the ideal dosage of oregano oil. Most supplements and essential oils have dosages specified by the manufacturers. These dosages take into account the oil’s most potent compounds, including thymol and carvacrol.

Do not exceed the dosage specified by the manufacturer. If you are looking for the ideal dosage for yourself, please consult your doctor.

Also, there is limited information on if you can actually ingest oregano essential oil. Do check with your healthcare provider. Some sources state that you must take a week-long break after using oregano oil every three weeks. The evidence backing this up is not solid. Your health care provider must be able to guide you better.

When Should You Visit A Doctor?

If you experience any of the following symptoms, please visit your doctor:

  • rashes
  • headaches
  • fatigue
  • stomach pain
  • difficulty swallowing
  • muscle pain

Infographic: Major Side Effects Of Oregano Oil

Oregano oil is an essential oil better known for its antimicrobial properties. It contains several beneficial chemical compounds that help treat many ailments. However, it may cause some negative reactions in some people. Check out the infographic below to learn about the major side effects of oregano oil.

major side effects of oregano oil (infographic)

Illustration: StyleCraze Design Team

The best way to avoid these symptoms is to consult your doctor. The oil is available in most health stores. Remember to go for a reputed brand and follow the manufacturer’s instructions to learn how to take oregano oil.

Overconsumption of oregano oil can lead to a number of problems. The side effects of oregano oil range from causing gastrointestinal issues to possibly lowering blood sugar levels. It may lead to heart or respiratory problems and in some cases, may trigger skin irritation. If possible, try to limit your intake or stay away from it entirely to avoid such complications.

Frequently Asked Questions

Does oregano increase blood pressure?

“No, oregano does not increase blood pressure. However, it can contribute to lowering one’s blood pressure”, says Jesse Feder, Clinical Dietitian at the Memorial Regional Hospital South.

Can oregano oil affect your period?

Jesse says, “Oregano oil is considered an emmenagogue, which can help stimulate normal menstrual activity, allowing for a normal cycle.” So oregano oil can correct menstrual problems.

Can oregano oil affect hormones?

According to Jesse, “Yes, oregano oil can affect certain hormones throughout our bodies. Specifically, it can increase progesterone and decrease levels of estrogen.”

Can you take oregano oil with antibiotics?

There is less information focusing on the possible interactions oregano oil may have with antibiotics. Please consult with your doctor.

How long can you take oregano capsules?

Consult a doctor to learn more about the frequency and dosage as it may differ from person to person. Moreover, excessive consumption may lead to side effects. Therefore, do not self-medicate.

Can I drink oregano oil in water?

Yes. Oregano oil in minute quantities can be safely consumed. Dilute this potent essential oil by adding a couple of drops to a glass of water.

Key Takeaways

  • Oregano oil may lead to negative drug interactions in people who take medications for diabetes due to its carvacrol (antioxidant found in oregano oil) content that helps lower blood sugar levels. .
  • It can also cause skin irritations in some people, especially in the case of oregano oil supplements. People allergic to the Lamiaceae family of plants are usually allergic to oregano and should avoid it unless inhaling the oil.
  • Oregano oil contains thymol which may cause cardiac and respiratory collapse; please be cautious when using this oil.
  • Pregnant women should avoid using oregano oil as it may induce abortions.
side effects of oregano oil

Image: Stable Diffusion/StyleCraze Design Team

Learn about the side effects of oregano oil before you incorporate it into your diet. From skin irritation to potential drug interactions, this oil seems to cause some serious trouble.

Personal Experience: Source


Articles on StyleCraze are backed by verified information from peer-reviewed and academic research papers, reputed organizations, research institutions, and medical associations to ensure accuracy and relevance. Read our editorial policy to learn more.

  1. Essential Oils of Oregano: Biological Activity beyond Their Antimicrobial Properties, Molecules, US National Library of Medicine, National Institutes of Health.
  2. Oregano, Drugs and Lactation Database, US National Library of Medicine, National Institutes of Health.
  3. Labiatae allergy: systemic reactions due to ingestion of oregano and thyme, Annals of Allergy, Asthma, and Immunology, US National Library of Medicine, National Institutes of Health.
  4. Are Essential Oils Safe? University of Minnesota.
  5. Carvacrol partially reverses symptoms of diabetes in STZ-induced diabetic rats, Cytotechnology, US National Library of Medicine, National Institutes of Health.
  6. Effects of a novel formulation of essential oils on glucose-insulin metabolism in diabetic and hypertensive rats: a pilot study, Diabetes, Obesity & Metabolism, US National Library of Medicine, National Institutes of Health.
  7. Herbal infusions used for induced abortion, Journal of Toxicology, US National Library of Medicine, National Institutes of Health.
  8. Drink Me and Abort Your Baby: The Herbal Abortion Tea, Craig Newmark Graduate School of Journalism.
  9. Herbs, Pediatric Pulmonary Division, Department of Pediatrics in the College of Medicine.
  10. Thymol
  11. Essential Oils of Oregano: Biological Activity beyond Their Antimicrobial Properties
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Serena Benali is a Registered Dietitian with over 3 years of experience and is also the founder of In Good Nutrition. Before opening the doors to her private practice, Serena worked as a culinary arts instructor, teaching people of all ages how to create delicious, nutritious meals and adopt a love for food and cooking. Serena also worked with the...read full bio

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