Describes results of experiments conducted to examine the antimicrobial activity of tea tree oil and tea tree oil products. Results were obtained by examining the in-vitro antimicrobial and sporicidal properties of tea tree oil-based skin formulations using European standard methods, and then to investigate their activity directly on human skin using an “ex-vivo” test as well as on volunteers in-vivo according to the European standard method. Several formulations containing tea tree oil met the requirements of the European standards for antiseptics. These formulations show potential in reducing hospital-acquired infections, such as those caused by S. aureus.