Abstract: A method and apparatus for performing modulated fluid delivery and aspiration during a surgical procedure such as phacoemulsification is provided. The method and apparatus include delivering fluid and/or aspirating fluid in a modulated or pulsed manner during a surgical procedure, including applying fluid and/or aspirating fluid in connection with ultrasonic energy at a level and for a time period sufficient to induce transient cavitation. Fluid may be applied and/or aspirated at a timing sequence and duty cycle similar to or different from application of ultrasonic energy delivery.