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Oregano (Origanum vulgare) is a Mediterranean herb from the mint family, Lamiaceae, most familiar in its dried form on pizza, in tomato sauces and in Greek and Mexican cooking. USDA data for dried oregano show useful amounts of vitamin K, vitamin E, iron and fiber gram for gram, but a teaspoon of leaves weighs about 1 gram, so a typical sprinkle adds only a little. This guide covers the USDA numbers for dried oregano, how oregano vs marjoram compare, what research on carvacrol and oregano benefits actually tested, and the cautions that apply: vitamin K for warfarin users, allergy, and why concentrated oregano products are a separate topic from the kitchen herb.
Peptide Labs does not sell culinary oregano. This article is general nutrition information, not medical advice.
Key Takeaways
- Oregano is a culinary herb in the mint family; marjoram is a close relative in the same genus.
- Per USDA, one teaspoon of dried oregano leaves has about 3 calories and 5% of the Daily Value for vitamin K; ground oregano packs more per teaspoon.
- USDA SR Legacy has no entry for fresh oregano, so the numbers here are for dried oregano only.
- Carvacrol research is mostly lab and animal work on essential oils; a 2018 review noted human trials were still lacking.
- People on warfarin should keep vitamin K intake steady, herbs included, and check diet changes with their clinician.
- Concentrated oregano extracts and oils are not food; they are covered in a separate article.
What oregano is, and which plant is in the jar
Botanically, oregano usually means Origanum vulgare, a herb of the Lamiaceae family that has been studied for its aromatic compounds (Soltani et al., Iranian Journal of Pharmaceutical Research, 2021). The name is used loosely in trade, though. The FDA list of spices generally recognized as safe for their intended use (21 CFR 182.10) files “oregano (oreganum, Mexican oregano, Mexican sage, origan)” under Lippia, a different genus, while the list of natural extractives (21 CFR 182.20) names Origanum species. In everyday terms, Mediterranean oregano and Mexican oregano are related in flavor but are not the same plant, and the label name alone does not always tell you which one you have.
Dried oregano nutrition (USDA)
The figures below are from USDA FoodData Central, SR Legacy entry FDC 171328, “Spices, oregano, dried”. Percent Daily Values use FDA reference amounts for adults (vitamin K 120 micrograms, iron 18 milligrams, manganese 2.3 milligrams, calcium 1,300 milligrams, fiber 28 grams). SR Legacy has no fresh oregano entry, so no fresh values are given here and none are estimated.
| Portion (USDA SR Legacy, FDC 171328) | Calories | Vitamin K | Iron | Manganese | Fiber |
|---|---|---|---|---|---|
| Dried oregano leaves, 1 tsp (1 g) | 3 | 6 mcg (5% DV) | 0.37 mg (2% DV) | 0.05 mg (2% DV) | 0.4 g (2% DV) |
| Ground dried oregano, 1 tsp (1.8 g) | 5 | 11 mcg (9% DV) | 0.66 mg (4% DV) | 0.09 mg (4% DV) | 0.8 g (3% DV) |
| Dried oregano, 100 g (reference only) | 265 | 622 mcg | 36.8 mg | 4.99 mg | 42.5 g |
The 100-gram row is there to show concentration, not as a realistic portion; a jar of dried oregano lasts most kitchens for months. USDA also lists 18.26 milligrams of vitamin E per 100 grams of dried oregano and only 25 milligrams of sodium, so the herb adds flavor while contributing almost no salt. Our low sodium foods guide explains where most sodium in a typical diet comes from.
Oregano vs marjoram
Marjoram is Origanum majorana, a close relative of oregano in the same genus and the same Lamiaceae family, widely used for cooking (Kakouri et al., Life, 2022). The FDA spice list still files sweet marjoram under the name Majorana hortensis, while recent papers use Origanum majorana. In the kitchen, the oregano vs marjoram difference is mostly flavor: marjoram is milder, sweeter and more floral, while oregano is sharper and more peppery. Many cooks add marjoram late, because its aroma fades with long cooking, and add dried oregano earlier.
| Feature | Oregano | Marjoram |
|---|---|---|
| Latin name | Origanum vulgare | Origanum majorana |
| USDA entry (dried) | FDC 171328 | FDC 170928 |
| Calories per 1 tsp (USDA) | 3 (1 g) | 2 (0.6 g) |
| Vitamin K per 1 tsp (USDA) | 6 mcg (5% DV) | 4 mcg (3% DV) |
| Iron per 1 tsp (USDA) | 0.37 mg (2% DV) | 0.50 mg (3% DV) |
| Flavor | Sharp, peppery, earthy | Mild, sweet, floral |
| Typical uses | Tomato sauces, pizza, grilled meats, beans | Soups, stuffings, eggs, light sauces |
USDA lists the same vitamin K value per 100 grams (621.7 micrograms) for both dried herbs, so the teaspoon difference comes mostly from marjoram’s lighter leaves. Either herb can stand in for the other; because oregano is stronger, start with less of it and taste as you go.
Oregano benefits: what the carvacrol research shows
Claims about oregano benefits almost always trace back to carvacrol and thymol, the aromatic compounds that dominate oregano’s essential oil. A 2018 review titled Carvacrol and human health summarized activities measured in lab dishes and animal models, then concluded that human trials were still lacking, which largely blocks conclusions about clinical relevance (Sharifi-Rad et al., Phytotherapy Research). A 2021 review of Origanum vulgare likewise focused on its chemistry and lab antimicrobial tests (Soltani et al.). Thymol, the main aromatic compound in thyme, is a close chemical relative of carvacrol.
None of this tells you what a sprinkle of dried oregano does in the body. The honest benefits of oregano as food are flavor, small amounts of vitamin K, vitamin E, iron and fiber, and a way to make vegetables and beans more appealing in herb-forward cooking such as the Mediterranean diet. Products sold as oregano extract or oil are a different category, and our oregano oil article covers that research and its side effects.
Vitamin K in dried oregano: a note for warfarin users
Dried oregano contains 621.7 micrograms of vitamin K per 100 grams in USDA data, about 9% of the Daily Value in a teaspoon of ground oregano. That is small next to leafy greens, but it adds up for people who cook with lots of dried herbs. The NIH Office of Dietary Supplements describes a serious and potentially dangerous interaction between vitamin K and warfarin and advises a consistent intake from food and supplements; MedlinePlus says to eat consistent amounts of vitamin K foods week to week and to talk to your doctor before changing your diet. Our vitamin K food guide lists the larger sources.
Oregano allergy
Oregano is not one of the nine major food allergens under US law, but allergy is documented. A 1996 case report described a patient with three systemic allergic reactions after eating oregano and thyme; skin tests were positive to several mint-family herbs, including marjoram, and the authors concluded the family seems to show cross-sensitivity (Benito et al., Annals of Allergy, Asthma and Immunology). A 2026 review notes that oregano contains Bet v 1-type allergens and profilins, protein groups that often explain cross-allergies with other spices and plants (Lisiecka, European Annals of Allergy and Clinical Immunology). If you react to oregano, mention related herbs such as thyme, rosemary and sage to an allergist.
Kitchen oregano vs concentrated products
Essential oils are not food. Poison Control (the National Capital Poison Center) warns that essential oils can be dangerous if swallowed, advises keeping bottles out of sight and reach of children, and lists 1-800-222-1222 for help. Capsules, drops and extracts are labeled and regulated differently from the herb in your spice rack, so read the label and ask a pharmacist or clinician if you take medicines.
Cooking with dried oregano
- Add dried oregano early to sauces, soups and bean dishes so it softens and blends in.
- Crumble dried leaves between your fingers over pizza or roasted vegetables to release aroma.
- Fresh oregano, when you can find it, tastes milder; a common rule of thumb is about three parts fresh to one part dried, adjusted by taste.
- Pair oregano with tomatoes, olives, feta-style cheeses, peppers, lemon and grilled vegetables.
- Store the jar airtight, away from the stove, and replace it when the aroma fades.
Frequently Asked Questions
Is oregano healthy?
Oregano is a low-calorie seasoning. Per USDA, a teaspoon of dried oregano leaves has about 3 calories and small amounts of vitamin K, iron and fiber. Its main contribution is flavor.
What does research say about oregano benefits?
As food, oregano adds flavor with almost no sodium and small amounts of nutrients. Research on its compound carvacrol is mostly lab and animal work, and a 2018 review noted that human trials were still lacking.
What is the difference in oregano vs marjoram?
Both are Origanum species in the mint family. Oregano is sharper and more peppery; marjoram is milder and sweeter. USDA lists similar nutrients per teaspoon for the dried herbs.
Is dried oregano as good as fresh?
Dried oregano is stronger gram for gram and is the form most recipes expect. USDA has no fresh oregano entry in SR Legacy, so a full nutrient comparison is not available from that source.
Does dried oregano have vitamin K?
Yes. A teaspoon of ground dried oregano gives about 9% of the Daily Value per USDA. People on warfarin should keep vitamin K intake consistent and talk to their clinician before changing their diet.
Is Mexican oregano the same as regular oregano?
Not botanically. The FDA spice list files Mexican oregano under Lippia, a different genus from the Origanum plants usually sold as Mediterranean oregano, although the flavors overlap.
Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines, are pregnant or have a food allergy. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed October 2026.
Related guides: Thyme: Nutrition, What Thyme Benefits Research Shows, Fresh vs Dried Thyme, Oregano Oil: What the Research Shows, Side Effects and Label Checks, Basil: Sweet Basil Nutrition, Fresh vs Dried and Safety, Marjoram: What It Is, Sweet Marjoram Nutrition and How to Use It.