Is it safe to eat rosemary and thyme?

November 18, 2025 •

4 min read

According to the U.S. Food and Drug Administration (FDA), rosemary extracts are Generally Recognized as Safe (GRAS) for use in food. Similarly, thyme is safe when used in common culinary amounts. This guide will detail whether it is safe to eat rosemary and thyme, outlining the precautions, benefits, and proper handling of these popular herbs.

Quick Summary

Both rosemary and thyme are safe for most individuals when used in standard culinary quantities. However, consuming large, concentrated doses, especially essential oils, can be unsafe and cause adverse effects. Special care is needed for pregnant women, those with specific health conditions, and individuals on certain medications.

Key Points

Culinary Use is Safe: Using rosemary and thyme in standard cooking amounts is safe for most healthy people.
Avoid High Doses: Concentrated doses, such as those found in supplements or undiluted essential oils, can cause adverse effects like vomiting, kidney irritation, and allergic reactions.
Pregnancy Precautions: Pregnant women should avoid medicinal amounts of both herbs due to the risk of uterine stimulation or hormonal effects.
Mind Medication Interactions: Both herbs can interact with blood-thinning and certain other medications, so consulting a doctor is essential if you are on prescription drugs.
Wash Fresh Herbs: Always wash fresh herbs thoroughly before consumption to remove dirt, bacteria, and debris.
Check for Allergies: Individuals with sensitivities to other plants in the mint family might experience allergic reactions to rosemary or thyme.

Safety of Consuming Rosemary

Rosemary is a robust and fragrant herb frequently used in cooking and traditional medicine. When consumed in typical culinary amounts, it is widely considered safe for most people. However, the safety profile changes significantly with higher, medicinal doses or in its concentrated essential oil form.

Potential Side Effects of High Doses of Rosemary

While a sprinkle of dried rosemary on potatoes is harmless, consuming large quantities of the leaf or ingesting its undiluted oil can be dangerous. Some potential side effects include:

Vomiting and stomach irritation
Kidney and liver irritation, especially with chronic, high-dose exposure
Increased sun sensitivity (photosensitivity) and skin redness
Uterine bleeding, which is a particular concern for pregnant women
Exacerbated seizure disorders

Medication Interactions with Rosemary

Rosemary can interact with certain medications due to some of its active compounds, including salicylate, a chemical similar to aspirin. Individuals taking the following types of medication should be cautious:

Blood-thinning medications: Rosemary might slow blood clotting and increase the risk of bruising and bleeding when taken with anticoagulants like warfarin or antiplatelet drugs.
Aspirin and salicylates: Combining rosemary with other salicylate-containing drugs may increase their effects and side effects.
Diabetes medications: Rosemary may lower blood sugar levels, so combining it with antidiabetes drugs could cause blood sugar to drop too low.

Safety of Consuming Thyme

Thyme is another common Mediterranean herb that is generally safe when consumed in culinary quantities. It is a versatile herb praised for its flavor and potential health benefits. However, as with rosemary, higher concentrations pose a risk.

Side Effects and Risks of Concentrated Thyme

Large, medicinal doses of thyme, particularly concentrated thyme oil, carry a higher risk of adverse effects. Some risks include:

Allergic reactions: People with allergies to other plants in the mint family, such as oregano or basil, may also be allergic to thyme.
Gastrointestinal issues: Excessive consumption can lead to stomach upset, nausea, dizziness, or headaches.
Hormonal effects: Some research suggests thyme can act like estrogen in the body, which is a concern for individuals with hormone-sensitive conditions like breast cancer or endometriosis.

Precautions and Interactions for Thyme

Surgery: Thyme might slow blood clotting. It is recommended to stop using thyme in medicinal amounts at least two weeks before a scheduled surgery.
Blood-thinning medications: Similar to rosemary, thyme can interact with medications that slow blood clotting, increasing the risk of bleeding.

Comparison: Rosemary vs. Thyme Safety Profile


Aspect	Rosemary (Rosmarinus officinalis)	Thyme (Thymus vulgaris)
Culinary Use	Generally safe for most people in standard cooking amounts.	Generally safe for most people in standard cooking amounts.
Medicinal Use (High Doses)	Possibly unsafe. Can cause vomiting, kidney irritation, and other issues.	Possibly unsafe, especially concentrated oil. May cause allergic reactions, dizziness, or GI issues.
Essential Oil	Undiluted oil is likely unsafe for internal use and can cause severe side effects.	Oral use of undiluted oil is not recommended and is considered possibly unsafe.
Pregnancy/Breastfeeding	AVOID medicinal amounts. May cause uterine stimulation. Stick to food amounts.	AVOID medicinal amounts. Potential hormonal effects and risk of miscarriage with oil. Stick to food amounts.
Specific Conditions	Caution with bleeding disorders, seizure disorders, and aspirin allergy.	Caution with bleeding disorders, hormone-sensitive conditions, and mint family allergies.
Medication Interactions	Can interact with anticoagulants, antiplatelets, and diabetes medications.	Can interact with anticoagulants and estrogen-sensitive drugs.

Proper Handling and Storage for Safety

Ensuring your culinary herbs are safe to eat also involves proper preparation and storage. Here is a brief guide to minimizing risks:

Wash thoroughly: Always rinse fresh herbs under running water to remove dirt, debris, and potential contaminants before use.
Use healthy plants: If you are harvesting from your garden, only use healthy, vibrant leaves and stems. Avoid any plants with pests or discoloration.
Mind the pesticides: If you use chemical pesticides on your plants, follow the recommended waiting period before harvesting. Using organic methods is ideal for edible plants.
Check for allergies: If you have known allergies to other mint-family plants, exercise caution when introducing rosemary and thyme into your diet.

Conclusion

In conclusion, incorporating rosemary and thyme into your cooking is generally safe and adds rich flavor and nutritional benefits. For the vast majority of healthy adults, using these herbs in typical culinary quantities is not a concern. However, the use of these herbs in high, medicinal doses or in their concentrated essential oil form is associated with significant risks and should be approached with caution or avoided entirely, especially for pregnant women, those with specific health conditions, or individuals on certain medications. By understanding the distinction between culinary and medicinal use, and by following safe handling practices, you can enjoy these potent herbs with confidence.

Frequently Asked Questions

Yes, it is safe to eat fresh rosemary and thyme from your garden, provided the herbs are properly identified, healthy, and washed thoroughly before use.

No, it is likely unsafe to ingest undiluted rosemary essential oil. The high concentration can cause serious side effects, including vomiting and kidney irritation.

Pregnant women, individuals with bleeding or seizure disorders, those with aspirin allergies, and people taking blood-thinning medications should avoid large, medicinal amounts of rosemary.

Yes, while uncommon, some individuals may be allergic to thyme, especially if they have allergies to other plants in the mint family, like oregano or basil.

Yes, both rosemary and thyme can affect blood pressure and may interact with medications used to control it. You should consult a doctor before using them in medicinal quantities.

Both herbs are rich in antioxidants and offer anti-inflammatory properties. Rosemary may benefit cognitive function, while thyme contains compounds with antibacterial effects.

During pregnancy and breastfeeding, it is safest to stick to culinary amounts and avoid medicinal doses of both herbs, as there is insufficient safety data and some risks associated with higher intake.