This study was carried out with the aim of investigating the cavitation threshold from 24 kHz to 5 MHz by measuring broad integrated voltage of white noise emitted from acoustic cavitation. Additionally, thresholds of chemical and mechanical effects were experimentally studied. Potassium iodide oxidation dosimetry was used to examine the threshold of chemical effect. The threshold of mechanical effect was quantified by observing the degradation of polyethylene oxide in aqueous solution of tert-butanol which was radical scavenger. All thresholds increased with increasing ultrasonic frequency. However, as compared with cavitation threshold, thresholds of chemical and mechanical effects were relatively higher at low frequency range (24 kHz to 500 kHz). This is because a certain amount of cavities is needed to produce these effects. The threshold of mechanical effect at very high frequencies (1 and 5 MHz) slightly changed perhaps due to the elevated acceleration in solution.