The Valsalva maneuver (VM) involves expiratory effort against a closed mouth and/or glottis in the sitting or supine position with the increased intraoral and intrathoracic pressure raised to 40 mmHg for 15-20 sec after which the pressure is suddenly released and the breathing restored to normal. Complex cardiovascular and other physiologic changes occur during the VM. The VM has been used for diagnostic and therapeutic reasons as well as intraoperatively during specific surgical procedures. Although the VM is usually safe, rare complications have been reported. This review examines the published literature surrounding the VM and explores the physiologic changes that occur during its performance. Attempts have been made to understand its intraoperative uses and complications and how these can be prevented.