Japanese scientists have found that powdered green tea matcha may reduce the frequency of sneezing in allergic rhinitis. In experiments on mice, the beverage significantly alleviated symptoms, acting not on the immune system but on the neural mechanisms that trigger the sneezing reflex. The study was published in the journal npj Science of Food.

Matcha is a bright green powder made from specially grown green tea leaves that are dried and ground. It is used for preparing drinks and as an additive in various foods. Previous research has shown that matcha contains a high amount of bioactive compounds, including antioxidants and amino acids, and may have beneficial effects on the cardiovascular system, brain, and inflammation.

Professor Osamu Kaminuma of the Research Institute for Radiation Biology and Medicine, Hiroshima University investigated whether matcha could help with allergic rhinitis — a common condition also known as hay fever.

“Studies involving humans indicate that green tea may ease allergic rhinitis symptoms, but the mechanism behind this effect remains unclear,” Kaminuma noted.

In the experiment, mice were induced with hay fever–like symptoms. The animals were given matcha two to three times a week for over five weeks, along with an additional dose 30 minutes before allergen exposure.

The results showed that mice receiving matcha experienced significantly fewer sneezing episodes. Interestingly, the tea had little effect on the main immune mechanisms of allergy.

Typically, an allergic reaction involves immunoglobulin E (IgE), mast cells, and T-lymphocytes. IgE triggers the release of histamine and other inflammatory substances that cause allergy symptoms. However, in this study, levels of these key immune markers remained almost unchanged.

Instead, matcha acted on the nervous system. Researchers studied the activity of the c-Fos gene, a marker of neuronal activation in response to strong stimuli. This gene is activated in a region of the brainstem associated with the sneezing reflex.

In allergic mice, c-Fos activity was sharply elevated. After consuming matcha, gene activity levels dropped almost to normal.

“Oral intake of matcha reduced sneezing without significantly affecting key immune markers. Instead, it suppressed activation of brainstem neurons involved in the sneezing reflex,” Kaminuma explained.

According to the study’s authors, matcha could potentially become a natural adjunct for alleviating allergic rhinitis symptoms, used alongside conventional therapy.