When Not to Use Rosemary: Health Risks, Interactions, and Precautions

December 5, 2025 •

3 min read

According to the American Pregnancy Association, while culinary amounts of rosemary are generally safe, medicinal doses are classified as possibly unsafe during pregnancy due to potential uterine stimulant effects. Knowing when not to use rosemary is crucial for preventing serious health risks, drug interactions, and adverse reactions. This guide provides essential information on situations where this herb should be avoided or used with caution.

Quick Summary

This guide details important warnings and contraindications for using rosemary, particularly in high concentrations or medicinal forms. It covers risks for certain health conditions, interactions with medications, and risks associated with pregnancy, breastfeeding, and use on children.

Key Points

Pregnancy and Breastfeeding: Avoid medicinal doses of rosemary as they may trigger uterine contractions and are considered possibly unsafe.
Seizure Disorders: The camphor content in concentrated rosemary can trigger seizures; therefore, individuals with epilepsy should not use it medicinally.
Blood Thinners: Rosemary can inhibit blood clotting, so use caution and consult a doctor if you take anticoagulant or antiplatelet drugs.
Essential Oil Ingestion: Never ingest undiluted rosemary essential oil, as it is toxic and can cause severe side effects like vomiting and kidney irritation.
Allergies and Skin Sensitivity: Those with allergies to mint family herbs should be cautious, and topical use of essential oil requires proper dilution to prevent irritation.
High Doses: Ingesting large, medicinal amounts of rosemary can lead to stomach irritation, kidney damage, and other adverse effects.

The fragrant herb rosemary (Rosmarinus officinalis) is a common ingredient in many cuisines and is also used for its purported health benefits. However, it is essential to be aware of the situations where its use, especially in concentrated forms like essential oil or supplements, can be harmful. Ingesting large amounts of rosemary can lead to serious side effects and interactions that may affect your health.

When to Avoid Rosemary: A Detailed Breakdown

During Pregnancy and Breastfeeding

For pregnant and breastfeeding women, caution is paramount when considering rosemary beyond standard culinary amounts. Large, medicinal doses of rosemary can have abortifacient and emmenagogue effects, meaning they can stimulate menstrual flow or uterine contractions. While small amounts of the herb used for seasoning food are typically safe, pregnant women should avoid rosemary supplements and concentrated oils unless advised otherwise by a healthcare provider. The safety of topical application during pregnancy is also not well-established, so it is best to avoid it. For breastfeeding women, sticking to food amounts is recommended until more reliable information is available.

With Certain Medical Conditions

Individuals with specific health issues should exercise extreme caution or completely avoid rosemary, particularly in high doses or concentrated forms. This includes those with seizure disorders due to rosemary's camphor content, bleeding disorders where it may slow blood clotting, and potential allergies, especially to other mint-family herbs. High doses have also been linked to potential kidney and liver issues, so those with pre-existing conditions should consult a doctor.

Alongside Certain Medications

Rosemary can interact with various medications. Consult a doctor if taking blood thinners (due to increased bleeding risk), ACE inhibitors (may interfere with action), diuretics (increased dehydration risk), diabetes medications (potential for low blood sugar), or lithium (potential for toxic levels).

Comparison Table: Safe vs. Unsafe Rosemary Use


Feature	Safe Use (Generally)	Unsafe Use (Potentially)
Form	Dried or fresh leaves in culinary amounts	Concentrated essential oil, high-dose supplements, undiluted oil
Application	Flavoring agent in foods, aroma diffusion	Ingestion of concentrated oils, topical use on open wounds, medicinal doses
Health Status	Healthy individuals without specific contraindications	Pregnant or breastfeeding women, individuals with epilepsy, bleeding disorders, or certain allergies
Dosage	Small amounts typical for cooking (a few grams)	Large, medicinal doses or regular, high-volume consumption
Topical Use	Diluted oil for minor issues (e.g., hair rinse)	Undiluted oil applied directly to skin

How to Avoid Unsafe Rosemary Use

Stick to Culinary Amounts: Use rosemary in moderation when cooking.
Avoid Undiluted Essential Oil: Never ingest concentrated rosemary essential oil; always dilute for topical use.
Consult a Healthcare Provider: Seek medical advice if pregnant, breastfeeding, have a medical condition, or take medication.
Perform a Patch Test: Test diluted topical oil on a small skin area first.

Conclusion

While rosemary is beneficial in moderation, high doses, concentrated forms, and supplements can be dangerous. Be cautious, especially if pregnant, breastfeeding, or have health conditions like seizure or bleeding disorders, or take certain medications. Always consult a healthcare professional if in doubt.

Lists for Further Consideration

Risks of High-Dose Rosemary Consumption

Gastrointestinal distress
Increased bleeding risk
Exacerbation of seizure disorders
Potential for uterine contractions
Photosensitivity

Alternatives to Rosemary

For flavor: Thyme or oregano.
For hair care: Diluted peppermint oil or other products.
For aromatherapy: Lavender or lemon essential oils.

When to Seek Medical Attention

Serious allergic reaction symptoms
Signs of seizure activity
Symptoms of overdose
Unexplained bleeding
Adverse reactions in pregnant or breastfeeding women

When Using Rosemary Topically

Dilute with a carrier oil: Always dilute rosemary essential oil.
Patch test is key: Test a small area of skin first.
Do not apply to open wounds: Avoid use on broken skin.

Outbound Link

For more information on the safety of essential oils, visit the National Association for Holistic Aromatherapy (NAHA) guidelines.

Frequently Asked Questions

Rosemary tea should be avoided in large quantities during pregnancy, as high doses may potentially trigger uterine contractions. Consuming it in very small, food-level amounts is generally considered safer, but it is best to consult a doctor.

The safety of applying rosemary essential oil topically during pregnancy is not fully established. Due to its high concentration and potential risks, it is best to avoid topical use unless specifically advised by a healthcare professional.

Yes, rosemary contains a chemical similar to aspirin called a salicylate. Taking rosemary along with aspirin can increase the effects and potential side effects of aspirin, so caution is advised.

No, individuals with seizure disorders should not use rosemary medicinally. The high camphor content in concentrated forms can have convulsant properties and may trigger seizures.

Cooking with small, culinary amounts of rosemary is generally considered safe. However, you should consult your healthcare provider before using it frequently or in medicinal amounts, as it can slow blood clotting and increase bleeding risk.

Ingesting undiluted rosemary essential oil is dangerous and can lead to serious side effects. Symptoms can include vomiting, stomach irritation, kidney damage, and potentially more severe reactions like spasms, coma, or pulmonary edema.

Individuals with sensitive skin, allergies to mint-family herbs, and pregnant or breastfeeding women should be cautious with topical rosemary oil. It should always be diluted with a carrier oil, and a patch test should be performed first.