Abstract: A sterilization method and apparatus uses ultrasonic vibrations and a sterilant bath, preferably ozone or hydrogen peroxide, for cleaning, disinfecting or sterilizing an article, whereby the ultrasonic vibrations generate cavitation microbubbles for damaging microbiological forms in the bath or on the article. The cavitation microbubbles have a diameter of 1-20 microns, preferably 1-10 microns. The use of cavitation microbubbles makes the method and apparatus more effective against microbiological forms. The cavitation microbubbles are generated at ultrasonic vibration frequencies above 100 k Hz and up to 2 Mhz, preferably 250 k Hz to 2 MHz and most preferably at about 500 k Hz.