Oregano Health Benefits and Side Effects

Written by: Christopher Karam | ✔️ Medically Reviewed by: Dr. Riad M., M.D - G.P and Micheal B., M.D | Last Updated: 2020 August 11

What Is Oregano?

Oregano (Origanum vulgare) is a flowering plant, that’s part of the mint family (Lamiaceae).

Oregano is a culinary perennial herb native to South Australia, Southwestern Eurasia, and the Mediterranean.

Its original scientific name is Origanum Vulgare and it has many healthy plant-based compounds, antioxidants, and nutritional benefits.

Oregano is also cultivated and found in Indian, Asian, Mexican, Turkish, Latin American, Mediterranean, and Greek cuisine.

sprigs of oregano and dried oregano in a bowl

Species of Oregano

Oregano has been an important component in many traditional medicines. Their leaves and flowers have been used for skin injuries and bruises. Its minty, strong scent and flavor can ease the pain of nausea and sore throats.

In different regions, oregano is also known as origanum, wild marjoram, pot marjoram, redbrush lippia (Mexican oregano), Ajwain (Indian).

The oregano genus has many different types and breeds, including:

  • Regular oregano (Scientific Name: Origanum vulgare)

  • Syrian oregano (Origanum syriacum)

  • Greek oregano (Origanum onites, Origanum dictamnus, and Hirtum)

  • Golden oregano (Origanum vulgare Aureum)

  • Ornamental oregano (Origanum vulgare sp. Gracile)

  • Italian oregano

  • Sweet marjoram

Oregano is closely related to marjoram and is often mistaken for marjoram plants

Flavor and Taste

In certain recipes, marjoram is often substituted for oregano for their somewhat similar flavor profile. Oregano has a pungent spicy flavor while marjoram is floral and woodsy, similar to thyme.

It’s most commonly used for cooking and seasoning dishes, but oregano can also be found in essential oils for making natural remedies and medicines.

Although oregano is generally associated with Italian food and cooking, it has been used throughout history with other cuisines and cultures.

Some species of oregano herbs are made from a completely different plant. For example, Mexican oregano (Lippia graveolens) is nicknamed “oregano” although it’s not part of the mint family.

The Origin and History of Oregano

Oregano is a sub-species of the mint family (Lamiaceae) and was originally grown in Western and Southwestern Eurasia (now called Europe and Asia) between 1600-1200 BC.

It was originally grown in Greece, through commercial trades and war, oregano made its way to Rome and shortly after to East Europe and North Africa.

Many subspecies of oregano have been cultivated worldwide, for over a thousand years. It’s been used for decorative purposes, to create medicines, and in cooking recipes.

The original species, origanum vulgare, had a comparatively bland taste when compared to other stronger tasting and unique species harvested in North African countries.

In Greek culture, oregano was believed to have been created by the Goddess Aphrodite as the plant looked appealing and was easy to cultivate.

The word “oregano” combines two Greek words, oros which means “mountain“ and ganos which means “joy”. Giving it the name “Joy of the Mountain”.

All over Greece, oregano was popularly used as an ornament for decorative purposes, and less so for cooking.

In ancient Greece, oregano was made into essential oils and used for medicinal treatments. It was used to treat:

  • Skin infections

  • Cuts

  • Cold sores

  • Sore muscles

  • Psoriasis

They also made non-herbal oregano tea, which was used to treat symptoms of:

  • Colds

  • Coughs

  • Lung infections

  • Tonsillitis

  • Asthma

Oregano essential oils were also widely used in traditional Chinese medicine. In China, eating oregano was used to relieve:

  • Cramps

  • Skin problems

  • Nausea

  • Digestive issues

Oregano has been used in ancient Egyptian medicine as a cure-all herb for treating:

  • Skin damage

  • Nausea

  • Cancer

Turkey, Iraq, Iran, Afghanistan, and India have been growing their native species of spicy and strong oregano herbs since 1250 BC, which are still growing to this day.

During the Elizabethan era, oregano was the primary cooking ingredient used in recipes and heavily cultivated, during this era it was a symbol of luck and good health.

Oregano wasn’t introduced to the United States until after World War 2, during the Italian Campaign. Between 1943 to 1945, U.S soldiers took oregano plants back home with them.

dried oregano and thyme in bowls

Cultivating, Harvesting, and Planting Oregano

Growing your own oregano plants at home can have many benefits. Oregano is a good companion herb to cultivate alongside other vegetables, herbs, spices, fruits, and flowers in your garden.

Companion herbs and plants prevent insects and discourage pests from coming near your garden. Acting as a natural insect repellent, fungus repellent, and pesticide.

In some cases, they also attract beneficial insects that help the plants grow faster.

Herbs, spices, fruits, and vegetables that grow and pair well with oregano include:

  • Cruciferous vegetables: broccoli, cauliflower, cabbage, and brussel sprouts

  • Vegetables: bell peppers, cucumbers, asparagus, carrots, corn, onions, tomatoes, beets, leeks, celery, and lettuce

  • Beans and legumes

  • Herbs and spices: thyme, basil, sage, marjoram, parsley, chives, rosemary, garlic, and dill

  • Flower and plants: lavender, tansy, and yarrow

There are no herbs, spices, fruits, and vegetables that don’t grow or pair well with oregano, but a lot wouldn’t benefit from having it grow alongside them.

You can start harvesting oregano once it reaches around 6 inches (15 cm) tall. Harvesting it regularly encourages leaf growth, which also prevents it from blooming or seeding.

If you’re looking to harvest the most leaves possible, you need to pick the leaves off the plant before it blooms.

When herbs and plants start to bloom, that’s where all of their energy goes and will generally cause them to have fewer leaves.

Avoid trimming back the plant by more than 20% of its height, as trimming more can damage the plant and stunt its growth.

How To Propagate Oregano Plants

  1. To propagate your oregano plants, clip a stem with a length of at least 4 inches (10 cm) long.

  2. Pick away the leaves from the bottom half of the stem and submerging it in a glass of water, keeping the section with leaves above the water. Keep them submerged for up to a week while avoiding direct sunlight.

  3. Change the water every few days until the trimming has developed roots.

  4. When the roots start to show, the trimming will be ready to be planted in soil.

How To Plant and Harvest Oregano

Planing oregano is also very straight forward. Here’s how to plant and harvest oregano:

  • Plant family: Lamiaceae (mint family)

  • Sowing time (planting time): You’re able to sow oregano seeds all year round but through February to April, you must sow the seeds indoors.

    You’re able to plant your thyme seeds outside through May to June. Germination usually occurs after 7 to 12 days, and seedlings usually appear between 14 to 20 days.

  • Flowering period: Late Spring to Summer (May to September), around 3 months after seedlings appear.

  • Harvest time: You’re able to harvest oregano all year round. While also waiting at least 30 days after transplanting or 50 days after seeding.

  • Transplanting: To propagate the thyme plant, cut young branches off the main stems keeping at least 75% of the plant’s height.

    Remove the leaves off the bottom half of the stalk, submerging it in a glass of water, keeping the section with leaves above the water. Transplanting only after the stems have grown roots.

  • Location and sun exposure: Full exposure to the sun, and any sunny location with good water drainage. Outdoor temperatures between 18 to 22 °C (64 to 72°F).

  • Soil quality: Fertile loam soil that has good drainage, watering thoroughly when the top of the soil is dry.

  • Soil pH: 6.0 to 7.0 (slightly acidic to neutral).

  • Soil temperature: Warm temperatures, around 15°C (59°F). Hot and damp soil will kill the plant.

Characteristics of The Plant

  • Plant height: Depending on the species, the oregano plant grows up to 1 to 3 feet tall.

  • Plant style: The oregano plant grows as a bush, with thick woodsy branches.

  • Leaf size: Oregano leaves reach a length of 2 inches long.

  • Leaf texture and style: The leaves are oval and round in shape, growing on square stems.

    They’re highly aromatic and full of essential oils. The leaves are dark green in color and are usually full of black spots, while other species are lighter in color and furry.

Most species of oregano have similar characteristics, having a bitter and pungent flavor with a strong earthy smell.

Other species of oregano, such as origanum vulgare hirtum (a type of Greek oregano) grow small soft fur teeth around its leaves.

The flavor of Greek oregano herbs is so strong that some species may numb your tongue when eaten fresh. Which is why it’s often dried, as it softens the flavor profile and reduces the pungency.

When cooking, professional chefs usually use whole sprigs of oregano to deepen the flavor of their food.

All types of oregano are used in professional and casual recipes, classic Italian dishes, and worldwide cuisines.

Due to its healthy nutrients and healthy plant-based compounds, oregano is full of powerful health benefits with few reported side effects.

fully grown oregano plants

Nutrition Facts of Oregano

Oregano is full of healthy plant-based compounds, antioxidants, and natural phytonutrients.

These have many health benefits, which include improving immune system strength, heart health, eyesight, and many other benefits.

Sprigs of oregano can be dried and will keep a very long shelf life. As long as it’s stored in a dry and cool area, most types of oregano can last up to 2 years in storage.

Phytonutrients

Phytonutrients are natural chemical compounds, including antioxidants and amino acids, that are found in fruits and vegetables.

These natural compounds protect food from insects, fungi, and germs as well as humans from oxidation.

These nutrients are not essential to maintaining life, but drastically improve the health of any living organism.

Oregano contains phytonutrients such as thymol and rosmarinic acid.

Thymol is a pleasant-smelling phytonutrient that’s mostly found in thyme. Thymol is very effective at reducing inflammation and preventing infection, as it has antibacterial and anti-inflammatory properties.

Multiple research studies have shown that thymol benefits and improves heart health, by reducing bad (LDL) cholesterol levels.

Rosmarinic acid has similar health benefits. Rosmarinic acid reduces inflammation, improves heart health, and treats airway-related diseases like asthma.

These polyphenols are found in most herbs and plants in the mint family (Lamiaceae) such as basil, rosemary, sage, thyme, hyssop, oregano, marjoram, lavender, mentha, and perilla.

Antioxidants

Antioxidants are healthy plant-based compounds that reduce oxidative damage that cells go through during metabolic processes.

Cell damage occurs during stress, illness, or environmental changes. Antioxidants can reduce and prevent the resulting oxidative damage.

These antioxidants make up the majority of oregano’s health benefits, as they’re highly antibacterial, antifungal, anti-inflammatory, and anticancer.

Vitamins and Minerals

Vitamins and minerals are essential micronutrients that most living organisms need for survival, especially for humans and large animals.

They’re necessary for all functions of the human body, from immune system strength to preventing heart disease.

Most essential vitamins and minerals can’t be made in the body, which means that these nutrients can only be found in a healthy diet.

Having a vitamin or mineral deficiency can have many side effects such as: fatigue, shortness of breath, dizziness, weight loss, weight gain, muscle weakness, lightheadedness, fainting, anemia, bone loss and weakness, nail yellowing, and loss of eyesight.

Vitamins can be taken as supplements in either a pill or liquid gel. Although supplementing with multivitamins can be a great backup plan, it should not be your main source for nutrition.

Nutrition Facts

The United States Department of Agriculture’s nutrition facts data (USDA) shows that oregano includes the following list of plant-based compounds and antioxidants such as:

  • Alpha-carotene

  • Apigenin

  • Beta-carotene

  • Lycopene

  • Luteolin

  • Quercetin

  • Rosmarinic acid

  • Scutellarein

The USDA’s Nutrient Database shows that oregano contains the following list of nutrients, vitamins, and minerals such as:

  • Vitamin A

  • Vitamin B6 (Pyridoxine)

  • Vitamin C

  • Vitamin E

  • Vitamin K

  • Calcium

  • Phosphorus

  • Potassium

  • Magnesium

  • Sodium

  • Folic acid

  • Riboflavin

  • Thiamin

  • Niacin

  • Iron

  • folate

  • Zinc

  • Myristicin

  • Eugenol

  • Alpha-thujene

  • Limonene

  • Calories (energy)

  • Fiber (carbohydrates)

  • Long-chain fatty acids

  • Protein

Cooking With Oregano

Mexican oregano is a great cooking ingredient that’s used worldwide, especially in recipes from Central America.

The most common type of oregano used for cooking is Mexican oregano, as its flavor is more complex with a slight undertone of lemon and a hint of citrus.

It goes very well with spicy dishes and roast meats since it improves and lightens the flavor.

Fresh oregano adds a vibrant taste to Italian and pesto dishes. Dried oregano works very well in Turkish meat recipes or Greek souvlaki.

There are many health benefits to cooking with oregano, it eases digestion while improving the taste of food.

Nearly all Mediterranean and Italian salads use Oregano frequently, it’s best used in a salad dressing with:

If you’re only looking for the flavor and its natural essential oils, you can add a few drops of oregano essential oil in a salad dressing.

For example, a popular salad used for weight loss and healthy eating is a feta, arugula, and tomato salad. Oregano works great for increasing the richness of the cheese and the sharpness of the tomato, also adding a deep herbal flavor.

In pasta dishes, adding fresh oregano and basil brightens up the entire recipe and gives a beautiful green color to the sauce, while also adding a lot of flavor.

Meat dishes drastically benefit from being seasoned with oregano. Adding oregano to pork, beef, or lamb strongly enhances the flavor and adds a mild woodsy aftertaste.

Since oregano naturally contains sodium (salt), it takes away the need to add a lot of table salt to your meals.

Oregano Health Benefits

1. Lowers Cholesterol Levels

Oregano essential oil is highly effective at lowering cholesterol levels. Most of which is due to its plant-based compounds carvacrol and thymol.

A study was conducted on mice suffering from high cholesterol, were given oregano supplements daily for 2 weeks. After the 2 weeks, the mice had reduced inflammation, edema, and LDL cholesterol.

Improving blood pressure and cholesterol levels also helped reduce the risk of cardiovascular disease (CVD).

dried oregano seasoning and leaves

2. Full of Antioxidants

Oregano contains a lot of powerful antioxidants, which repair and prevent cell damage. Oregano contains more antioxidants than most cooking herbs.

The antioxidants found in oregano heavily contribute to its list of health benefits. Oregano contains the following antioxidants:

  • Thymol

  • Carvacrol

  • Limonene

  • Terpinene

  • Ocimene

  • Caryophyllene

The antioxidants drastically reduce inflammation, the risk of developing cancer, type 2 diabetes, cardiovascular disease, along with other diseases.

Hundreds of studies and research papers found that its antioxidants also fights off free radicals, which cause cancer and ageing to healthy cells.

3. Oregano Is Highly Antibacterial

Oregano has natural antibacterial plant compounds, similar to coconut oil. Its antibacterial properties have a wide range of benefits, most of which prevent some types of infection or illness.

Antibacterial herbs and spices can prevent diseases and illnesses such as:

  • Cancer

  • Skin infections: acne, folliculitis, cellulitis, impetigo (school sores), furunculosis methicillin, staphylococcal scalded skin syndrome, dermatitis, athlete’s foot, yeast infections, shingles, warts, herpes simplex, and eczema.

  • Oral infections: gingivitis causing cavities (caries), periodontitis, lactobacillus acidophilus, periodontal disease, thrush, canker sores, and oral herpes.

  • Hay fever

  • The common cold

  • Coronavirus (COVID-19)

  • Strep throat

  • Urinary tract infections (UTIs)

  • Tuberculosis

  • Pneumonia

  • Upper respiratory tract infections

  • E. coli

  • Salmonella

  • Shigella

  • Bacterial meningitis

  • Gastritis

Adding oregano to your diet can be a great way to amplify your immune system strength and can even boost the effectiveness of medicinal drugs and treatments.

Multiple studies have shown that oregano essential oil was able to fight against 11 highly resistant strains of microbes and 13 pathogens.

Antibacterial herbs and spices are most effecting at fighting off bacteria that are common with respiratory and urinary tract infections.

Another benefit is that they increase your resistance to Escherichia coli (E. coli) and Pseudomonas Aeruginosa bacteria.

Adding oregano to your balanced diet will drastically boost your immune system strength. Other antibacterial foods include:

4. Oregano Reduces Inflammation

Chronic inflammation is long-term inflammation that’s caused by a poor diet, stress, infections, and autoimmune disorders. Inflammation can cause a variety of diseases and disorders such as:

  • Rheumatoid arthritis

  • Cardiovascular disease

  • Heart disease

  • Cancer

  • Diabetes

  • Asthma

  • Alzheimer’s disease

  • Leaky gut syndrome

A study has found that the plant-based compounds and antioxidants in oregano leaves were able to reduce over 11 markers of inflammation.

Another study found that patients who took oregano oil daily for 4 weeks, had improved intestinal health, reduce flatulence, and reduced bloating.

growing oregano plants

Oregano Side Effects and Detriments

1. May Cause Nausea and Discomfort

Oregano is full of plant compounds and chemicals that may cause nausea and discomfort. High concentrations of phenolic acids can upset your stomach due to how concentrated they are.

This is amplified when oregano is taken on an empty stomach, since your liver hasn’t stored any glucose, the high concentrations of plant compounds aren’t diluted.

This has similar effects to strong teas such as earl grey tea, green tea, and white tea.

Rating and Recommendation

Extremely Recommended

Oregano is among the most thoroughly researched herbs, with over 100 clinical studies proving its large list of benefits.

Its widely used in cooking recipes across Europe since it adds a lot of earthy, pungent, and spicy flavors.

Cooking with oregano offers many health benefits with very few side effects. Most of which stem from its healthy plant compounds, reducing inflammation as well as improving heart and brain health.

Oregano is also an excellent addition to your garden and a good companion herb to cultivate.

Here’s the full list of the health benefits of Oregano:

  1. Lowers Cholesterol Levels

  2. Full of Antioxidants

  3. Oregano Is Highly Antibacterial

  4. Oregano Reduces Inflammation

Here’s the list of side effects of Oregano:

  1. May Cause Nausea and Discomfort

It’s also found in certain types of medicine and thymol is used in many over-the-counter drugs, for its antibacterial and antifungal properties.

As an essential oil, oregano also is a popular scent used in diffusers, which may also help clear sinuses and mucus buildup.

Oregano essential oil is used in skin care products and medications to recover from wounds faster, reduce inflammation and redness, soothes itchiness, irritation, and darkness of bruises.

If you’re suffering from hay fever, the flu, or respiratory infections, oregano can help relieve some of your symptoms.

Overall, oregano is a highly versatile cooking ingredient that’s beneficial to your health, and great for gardening as well as cooking.

Frequently Asked Questions

Oregano (Origanum Vulgare) is a flowering plant, that’s part of the mint family (Lamiaceae).

Oregano is a culinary perennial herb native to South Australia, Southwestern Eurasia, and the Mediterranean.

Its original scientific name is origanum vulgare and it has many healthy plant-based compounds, antioxidants, and nutritional benefits.

Oregano is also cultivated and found in Indian, Asian, Mexican, Turkish, Latin American, Mediterranean, and Greek cuisine.

Planing oregano is also very straight forward. Here’s how to plant and harvest oregano:

Plant family: Lamiaceae (mint family)

Sowing time (planting time): You’re able to sow oregano seeds all year round but through February to April, you must sow the seeds indoors.

You’re able to plant your thyme seeds outside through May to June. Germination usually occurs after 7 to 12 days, and seedlings usually appear between 14 to 20 days.

Flowering period: Late Spring to Summer (May to September), around 3 months after seedlings appear.

Harvest time: You’re able to harvest oregano all year round. While also waiting at least 30 days after transplanting or 50 days after seeding.

Transplanting: To propagate the thyme plant, cut young branches off the main stems keeping at least 75% of the plant’s height.

Remove the leaves off the bottom half of the stalk, submerging it in a glass of water, keeping the section with leaves above the water.

Transplanting only after the stems have grown roots.

Location and sun exposure: Full exposure to the sun, and any sunny location with good water drainage. Outdoor temperatures between 18 to 22 °C (64 to 72°F).

Soil quality: Fertile loam soil that has good drainage, watering thoroughly when the top of the soil is dry.

Soil pH: 6.0 to 7.0 (slightly acidic to neutral).

Soil temperature: Warm temperatures, around 15°C (59°F). Hot and damp soil will kill the plant.

In certain recipes, marjoram is often substituted for oregano for their somewhat similar flavor profile. Oregano has a pungent spicy flavor while marjoram is floral and woodsy, similar to thyme.

It’s most commonly used for cooking and seasoning dishes, but oregano can also be found in essential oils for making natural remedies and medicines.

Although oregano is generally associated with Italian food and cooking, it has been used throughout history with other cuisines and cultures.

Oregano essential oil is used in skin care products and medications to recover from wounds faster, reduce inflammation and redness, soothes itchiness, irritation, and darkness of bruises.

If you’re suffering from hay fever, the flu, or respiratory infections, oregano can help relieve some of your symptoms.

Overall, oregano is a highly versatile cooking ingredient that’s beneficial to your health, and great for gardening as well as cooking.

Articles and Sources

1. J Tradit Chin Med. (2013 December 06) Parsley: a review of ethnopharmacology, phytochemistry and biological activities.

2. Molecules. (2019 May 17) Chemical Composition and Biological Activities of Oregano Essential Oil and Its Fractions Obtained by Vacuum Distillation

3. Molecules. (2017 June 14) Essential Oils of Oregano: Biological Activity beyond Their Antimicrobial Properties

4. Front Microbiol. (2018 October 05) Bactericidal Property of Oregano Oil Against Multidrug-Resistant Clinical Isolates

5. J Appl Microbiol. (2014 May 05) Antiviral efficacy and mechanisms of action of oregano essential oil and its primary component carvacrol against murine norovirus

6. Biochim Open. (2017 March 03) Anti-inflammatory, tissue remodeling, immunomodulatory, and anticancer activities of oregano (Origanum vulgare) essential oil in a human skin disease model

7. Med Dosw Mikrobiol. (2012 March 04) [The antibacterial activity of oregano essential oil (Origanum heracleoticum L.) against clinical strains of Escherichia coli and Pseudomonas aeruginosa]

8. J Zhejiang Univ Sci B. (2017 January 01) Chemical composition and antioxidant activities of essential oils from different parts of the oregano

9. Pathogens. (2019 January 28) Antimicrobial Activity of Six Essential Oils Against a Group of Human Pathogens: A Comparative Study

10. Appl Environ Microbiol. (2014 August 16) Mechanisms of Antiviral Action of Plant Antimicrobials against Murine Norovirus

11. Plants (Basel). (2018 March 01) Flavonoids and Phenolic Acids from Oregano: Occurrence, Biological Activity and Health Benefits

12. Front Microbiol. (2016 May 23) Synergistic and Additive Effect of Oregano Essential Oil and Biological Silver Nanoparticles against Multidrug-Resistant Bacterial Strains

13. Heliyon. (2019 October 11) Oregano: A potential prophylactic treatment for the intestinal microbiota

14. Evid Based Complement Alternat Med. (2016 December 20) Antimicrobial Properties of Plant Essential Oils against Human Pathogens and Their Mode of Action: An Updated Review

15. Biomed Res Int. (2016 May 29) Oregano Essential Oil Improves Intestinal Morphology and Expression of Tight Junction Proteins Associated with Modulation of Selected Intestinal Bacteria and Immune Status in a Pig Model

16. PLoS One. (2019 December 10) Oregano powder reduces Streptococcus and increases SCFA concentration in a mixed bacterial culture assay

17. Molecules. (2017 June 14) Essential Oils of Oregano: Biological Activity beyond Their Antimicrobial Properties

18. Molecules. (2018 August 28) Origanum vulgare L. Essential Oil as a Potential Anti-Acne Topical Nanoemulsion—In Vitro and In Vivo Study

19. Iran J Pharm Res. (2013 April 02) Antinociceptive Effect of Aqueous Extract of Origanum vulgare L. in Male Rats: Possible Involvement of the GABAergic System

20. Molecules. (2019 June 11) Essential Oils as Antimicrobial Agents—Myth or Real Alternative?

Oregano Nutrition Facts

Serving Size 100 g (about 3.5 Oz or 0.44 cups)

Amount Per Serving
Calories 265 Calories from Fat 39
% Daily Value*
Total Fat 4.3 g 5 %
Saturated Fat 1.55 g 6 %
Polyunsaturated fat 1.37 g
Monounsaturated fat 0.72 g
Trans Fat 0 g
Cholesterol 0 mg 0 %
Sodium 25 mg 2 %
Potassium 1.26 g 35 %
Total Carbohydrate 68.92 g 23 %
Dietary Fiber 42.5 g 167 %
Sugars 4.1 g
Protein 9 g 18 %
Vitamin A 190 % Vitamin C 3 %
Vitamin E 120 % Vitamin K 516 %
Vitamin D 0 % Vitamin B6 77 %
Calcium 160 % Iron 462 %
Magnesium 67.5 % Cobalamin 0 %

Calories per gram:

Fat: 9 | Carbohydrate: 4 | Protein: 4

Source: USDA's Nutrient Database

 

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