When I was a child, my best friend’s grandmother – we called her “Petite Mère” – used to set up an evergreen tree at Christmastime whose fragrance blended with the smells of the fireplace and the cooking aromas. At this time of year, too, I celebrated Hanukkah at my grandmother’s house, which was warm and inviting with the scent of burning menorah candles, latkes and roast chicken.

Many decades later, the aroma of my own fireplace brought back those happy childhood memories, comforting me after my mother’s death.

Smell and taste have similar ways of invoking powerful memories. When odor molecules reach the olfactory organ at the top of the nose, they activate a direct nerve pathway to memory and emotion centers in the brain, so smells and taste quickly spark memories that can influence your mood.

Scents that trigger comforting memories help turn on the brain’s relaxation response and lower the stress response, which reduce pain and benefit the immune system. Some odor molecules have been shown in laboratory experiments to have potent effects on the functioning of the brain and immune system. Lavender, for example, eases tension and induces sleep. It even changes brainwaves to patterns seen in relaxed states and during sleep.

When we used to help Petite Mère set up her crèche, I wondered why two of the three wise men brought gifts of frankincense and myrrh. Why not diamonds and rubies? It turns out that these fragrant resins were highly valued in ancient times for their healing properties. Historical and biblical texts are peppered with references to special resins, oils and balms with healing powers, and the length to which believers would go to protect them. Greek soldiers carried myrrh into battle to treat wounds, and frankincense was burned in censers during Catholic Masses partly to rid pilgrims of infectious diseases.

Studies today show that frankincense does indeed have properties that affect the immune system; in some cases it reduces inflammation, and in others it stimulates white blood cells to fight fungal and bacterial infections. There is still much work to be done to show whether and how these essential oils work, and in what circumstances patients with different illnesses might benefit from using them. You can, nonetheless, take advantage of some of the healing benefits of aromas.

Aromatherapy is branch of integrative medicine that employs essential oils, many whose fragrances can trigger old memories or be used to create positive new ones – for instance, by repeatedly having a massage with a favorite scent.

I have jasmine and gardenia plants and herbs whose fragrances remind me of Crete, where I recuperated from a major flare of my inflammatory arthritis and from the stress of my mother’s death. In summer, their fragrance mingles with the smell of the mosquito candle’s wax, bringing back faint memories of those Hanukkahs long ago. And after a stressful day, those scents help relax me, so I’m ready for a good night’s sleep.

Esther M. Sternberg, MD, rheumatologist and researcher, is the author of Healing Spaces: The Science of Place and Well-being (Harvard University Press, 2009).