Hi, thanks for your question. Octenidine dihydrochloride is a compound that is used in some antiseptic and deodorant products. It is a surfactant and potent antibacterial agent, effective at reducing the growth of bacteria on the skin, which can help to reduce body odor. Its use in the armpits is considered safe, however, it may cause skin irritation or an allergic reaction. In general it will cause a temporary improvement in underarm odor, as bacteria are killed. In the long run, it may stimulate the malodorous and more resistant bacteria to thrive, but more research is need to know the true impact. Best, Chris