The research on rosemary's health benefits is limited - here's what you need to know

• Rosemary's health benefits are largely based on scientific studies in animal models and test tubes, and therefore should not be taken as medical advice.
• Consuming too much rosemary over long periods of time may pose a problem if you're on certain medications like anticoagulants, ACE inhibitors, or diuretics.

Rosemary is a plant that is native to the Mediterranean region and is formally called Rosmarinus officinalis. You can use rosemary in many different forms, including as a fresh herb, dried herb, essential oil, and powder extract.

Rosemary has attracted attention for possible health benefits because it contains antioxidants - compounds that may protect against inflammation and certain inflammatory diseases. However, research results are mixed and more studies are needed to confirm these potential benefits.

Here's more information on rosemary's many uses as well as precautions linked to the plant.

How to best use rosemary

Rosemary is a versatile, fragrant herb. Here are just a few popular ways to use it:

• With food: Rosemary helps to season foods if you are looking for alternatives, or additions, to salt. It goes great with meat like lamb, chicken, or fish, as well as staples like quinoa, brown rice, mushrooms, or potatoes. Follow recipe recommendations as they can vary depending on whether you're using fresh or dried rosemary. For example, this quinoa recipe from New York Presbyterian Hospital calls for eight sprigs of fresh rosemary or 1½ tablespoons of the dried herb.
• In drinks: You can make rosemary tea, or you can add fresh rosemary to alcoholic and non-alcoholic drinks like lemonade and some cocktails.
• As fragrance: If you have rosemary essential oil, you can add three to four drops of it to a diffuser to enjoy its distinct aroma.
• As mosquito repellant: Grow rosemary around your home, or use essential oils to create a body spray that can help repel pesky mosquitoes. Reapply the body spray every two hours.

What the research says about rosemary's health benefits

Most research around the health benefits of rosemary is either in animal models or test tubes. And the limited research conducted on humans is mostly small studies that may not be relevant to the general public.

Therefore, it's important to consult a healthcare professional if you're considering taking rosemary for your health. Here's what the limited research on rosemary, involving humans, has found:

• A small 2012 study found improved cognitive performance and mood in subjects who were exposed to the aroma of rosemary.
• A small 2017 study of people with Type 2 diabetes found that rosemary powder helped to reduce hemoglobin A1c, a measurement used to indicate blood sugar control.
• Rosemary has long been used as a home remedy to treat indigestion, says Kimberly Langdon, MD, an OB-GYN at Medzino, an online service connecting patients to doctors and pharmacies. You can try it in tea or essential oil form.

Risks and side effects of rosemary

Although users tout rosemary's many benefits, it has some risks if you use too much - and some people need to proceed with caution.

Registered dietitian nutritionist Rhyan Geiger, owner of Phoenix Vegan Dietitian, says that if you're on any of the following types of medications, talk to your doctor before adding rosemary to your diet because it may work similarly to the medicines below, and that could lead to unwanted or even serious side effects:

• Anticoagulants, a type of medication that thins the blood. Heparin and warfarin are commonly prescribed anticoagulants. There's some evidence to suggest that long-term use of rosemary can make it more difficult for blood to clot, which may cause more frequent bruising and bleeding if taken in combination with anticoagulants.
• ACE inhibitors, which are used to treat high blood pressure. Some common brand names include Monopril and Prinivil. Substances in rosemary have been found to bind to the same molecule as these medications.
• Diuretics are used to increase urination and help rid the body of extra fluid. You may be advised to use a diuretic for kidney disorders or heart failure. Some common examples of diuretics include Lasix and Diamox. A rat study from 2000 found that rosemary may have a diuretic effect, which is why you might see warnings not to mix it with diuretic medications because you could increase the risk of dehydration and other side effects.
• Lithium, which is used to treat symptoms of bipolar disorder. Rosemary's potential diuretic effects are why healthcare professionals will sometimes caution against mixing the two because it could lead to abnormally high lithium levels in the body.

You might also want to avoid rosemary in supplement form while pregnant, Langdon says. While small amounts of rosemary used in food are not considered dangerous, there isn't enough known about rosemary in supplement form and its potential interactions in pregnant and nursing people.

When buying rosemary as an essential oil or powder extract, read the label to check for third-party testing, Langdon advises. This helps ensure the product does not have contaminants such as heavy metals. You can tell if a product has third-party testing by looking for a stamp of certification.

Insider's takeaway

Rosemary is an herb best used in food, drinks, fragrances, and as an insect repellent.

It's a useful flavoring agent, but don't depend on it for some of the purported health benefits associated with rosemary. More thorough research is needed to fully understand rosemary's effects on physical and mental wellbeing.

Moreover, if you use medications such as ACE inhibitors or anticoagulants, check with your doctor before adding rosemary to your diet.

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