Background

Rosemary (Rosmarinus officinalis) is an herb native to the Mediterranean region. The leaf and its oil are commonly used in food and also to make medicine.

Rosemary seems to increase blood circulation when applied to the scalp, which might help hair follicles grow. Rosemary extract might also help protect the skin from sun damage.

People commonly use rosemary for memory, indigestion, fatigue, hair loss, and many other purposes, but there is no good scientific evidence to support most of these uses.

Safety Safety definitions

When taken by mouth: Rosemary is commonly consumed in foods. Rosemary leaf is possibly safe for most people when taken as a medicine for up to 8 weeks. But taking undiluted rosemary oil or very large amounts of rosemary leaf is likely unsafe. Taking large amounts of rosemary can cause vomiting, sun sensitivity, and skin redness.

When applied to the skin: Rosemary oil is possibly safe for most people. It might cause allergic reactions in some people.

When inhaled: Rosemary is possibly safe for most people when used as aromatherapy.

Special Precautions & Warnings:

Pregnancy: Rosemary is commonly consumed in foods. Rosemary is possibly unsafe when taken by mouth in medicinal amounts during pregnancy. It might cause a miscarriage. There isn't enough reliable information to know if rosemary is safe when applied to the skin when pregnant. Stay on the safe side and avoid use.

Breast-feeding: There isn't enough reliable information to know if rosemary is safe to use as medicine when breast-feeding. Stay on the safe side and stick to food amounts.

Aspirin allergy. Rosemary contains a chemical that is very similar to aspirin. This chemical may cause a reaction in people who are allergic to aspirin.

Bleeding disorders: Rosemary might increase the risk of bleeding and bruising in people with bleeding disorders. Use cautiously.

Seizure disorders: Rosemary might make seizure disorders worse. Don't use more than amounts found in foods.

Effectiveness

Dosing & administration

Rosemary is commonly consumed as a spice and flavoring in foods.

Rosemary oil, powder, and extract have also been used by adults as medicine. There isn't enough reliable information to know what an appropriate dose of rosemary might be. Keep in mind that natural products are not always necessarily safe and dosages can be important. Be sure to follow relevant directions on product labels and consult a healthcare professional before using.

Interactions with pharmaceuticals

Aspirin

Interaction Rating=Moderate Be cautious with this combination.

Rosemary contains chemicals similar to aspirin. Taking rosemary along with aspirin might increase the effects and side effects of aspirin.

Choline Magnesium Trisalicylate (Trilisate)

Interaction Rating=Moderate Be cautious with this combination.

Rosemary contains chemicals that are similar to choline magnesium trisalicylate. Taking rosemary along with choline magnesium trisalicylate might increase the effects and side effects of choline magnesium trisalicylate.

Medications changed by the liver (Cytochrome P450 1A2 (CYP1A2) substrates)

Interaction Rating=Minor Be watchful with this combination.

Some medications are changed and broken down by the liver. Rosemary might change how quickly the liver breaks down these medications. This could change the effects and side effects of these medications.

Medications for diabetes (Antidiabetes drugs)

Interaction Rating=Moderate Be cautious with this combination.

Rosemary might lower blood sugar levels. Taking rosemary along with diabetes medications might cause blood sugar to drop too low. Monitor your blood sugar closely.

Medications that slow blood clotting (Anticoagulant / Antiplatelet drugs)

Interaction Rating=Moderate Be cautious with this combination.

Rosemary might slow blood clotting. Taking rosemary along with medications that also slow blood clotting might increase the risk of bruising and bleeding.

Salsalate (Disalcid)

Interaction Rating=Moderate Be cautious with this combination.

Salsalate is called a salicylate. Rosemary also contains a salicylate. Taking salsalate with rosemary might increase the risk for side effects from salicylates.

Interactions with herbs & supplements

Herbs and supplements that might lower blood sugar: Rosemary might lower blood sugar. Taking it with other supplements with similar effects might lower blood sugar too much. Examples of supplements with this effect include aloe, bitter melon, cassia cinnamon, chromium, and prickly pear cactus.
Herbs and supplements that might slow blood clotting: Rosemary might slow blood clotting and increase the risk of bleeding. Taking it with other supplements with similar effects might increase the risk of bleeding in some people. Examples of supplements with this effect include garlic, ginger, ginkgo, nattokinase, and Panax ginseng.
Herbs that contain chemicals similar to aspirin (salicylates): Rosemary contains chemicals called salicylates. Salicylates are similar to aspirin. Taking it with other supplements that contain salicylates might increase their effects and side effects. Examples of supplements that contain salicylates include aspen, black haw, poplar, meadowsweet, and willow bark.
Iron: Rosemary can decrease the absorption of iron from foods. It is possible that rosemary might also decrease the absorption of iron from supplements when taken at the same time. But it isn't clear if this is a big concern.

Interactions with foods

Rosemary can decrease how much iron the body absorbs from foods. But it isn't clear if this is a big concern.