A common herb shows promise for boosting brain health and fighting Alzheimer’s

Rosemary (Rosmarinus officinalis), the aromatic herb native to the Mediterranean, has long been treasured in kitchens around the world. But beyond its culinary charm, rosemary is also gaining recognition for its impressive health benefits, especially when it comes to brain health, inflammation and immune function.

Research suggests rosemary may even hold promise in the fight against Alzheimer’s disease, the leading cause of dementia worldwide.

Historically, rosemary has been linked to memory and mental clarity. In ancient Greece and Rome, students and scholars used rosemary in the hope of sharpening concentration and recall.

Modern science is finding there may have been something in this: in one study, people who inhaled rosemary’s scent performed better on memory tasks compared to those in an unscented environment.

So how does rosemary work on the brain? There are several mechanisms at play. For starters, rosemary stimulates blood circulation, including to the brain, helping deliver more oxygen and nutrients, which may improve mental clarity. It also has calming properties; some studies suggest its aroma can reduce anxiety and improve sleep. Lower stress can mean better focus and memory retention.

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Rosemary contains compounds that interact with the brain’s neurotransmitters. One such compound, 1,8-cineole, helps prevent the breakdown of acetylcholine, a brain chemical essential for learning and memory. By preserving acetylcholine, rosemary may help support cognitive performance, especially as we age.

Another bonus? Rosemary is packed with antioxidants, which help protect brain cells from damage caused by oxidative stress – a major factor in cognitive decline.

Rosemary is rich in phytochemicals, plant compounds with health-enhancing effects. One of the most powerful is carnosic acid, an antioxidant and anti-inflammatory agent that helps shield brain cells from harm, particularly from the kinds of damage linked to Alzheimer’s disease.

In 2025, researchers developed a stable version of carnosic acid called diAcCA. In promising pre-clinical studies, this compound improved memory, boosted the number of synapses (the connections between brain cells), and reduced harmful Alzheimer’s related proteins like amyloid-beta and tau.

What’s especially exciting is that diAcCA only activates in inflamed brain regions, which could minimise side effects. So far, studies in mice show no signs of toxicity and significant cognitive improvements – raising hopes that human trials could be next.

Researchers also believe diAcCA could help treat other inflammatory conditions, such as type 2 diabetes, cardiovascular disease and Parkinson’s disease.

Beyond brain health

Rosemary’s benefits could extend well beyond the brain. It’s been used traditionally to ease digestion, relieve bloating and reduce inflammation.

Compounds like rosmarinic acid and ursolic acid are known for their anti-inflammatory effects throughout the body. Rosemary may even benefit the skin – a review suggests it can help soothe acne and eczema, while carnosic acid may offer anti-ageing benefits by protecting skin from sun damage.

Rosemary oil also has antimicrobial properties, showing promise in food preservation and potential pharmaceutical applications by inhibiting the growth of bacteria and fungi.

For most people, rosemary is safe when used in food, teas or aromatherapy. But concentrated doses or extracts can pose risks. Consuming large amounts may cause vomiting or, in rare cases, seizures – particularly in people with epilepsy.

There’s also a theoretical risk of rosemary stimulating uterine contractions, so pregnant people should avoid high doses. Because rosemary can interact with some medications – such as blood thinners – it’s best to check with a healthcare provider before taking large amounts in supplement form.

Rosemary is more than just a kitchen staple. It’s a natural remedy with ancient roots and modern scientific backing. As research continues, particularly into breakthrough compounds like diAcCA, rosemary could play an exciting role in future treatments for Alzheimer’s and other chronic conditions.

In the meantime, adding a little rosemary to your life – whether in a meal, a cup of tea, or a breath of its fragrant oil – could be a small step with big health benefits.

This article is republished from The Conversation under a Creative Commons license. Read the original article.