In this prospective, randomised, crossover in-vivo laboratory study the bactericidal activity of conventional WHO formulations WHO I (ethanol 80 % v/v) and WHO II (isopropanol 75 % v/v) in hygienic hand disinfection was investigated according to EN 1500. In addition, modified WHO formulations were tested with 80 and 75 % wt/wt of the respective alcohol. The conventional formulations were applied for 1 x 3 mL/30 seconds and 2 x 3 mL/2 x 30 seconds, while the modified formulations were only applied for 1 x 3 mL/30 seconds. All formulations were tested against a reference (isopropanol 60 % v/v, 2 x 3 mL for 2 x 30 seconds). The WHO formulations were found to be effective according to EN 1500 within 60 seconds, however not within 30 seconds. The respective modified formulations satisfied EN 1500 also within 30 sections.