Nitrous oxide is a gas that has anxiolytic, amnestic, and mild-to-moderate analgesic properties. Patients describe a detached or "floating" sensation but typically remain awake during the procedure and are able to follow commands while breathing the gas. Nitrous oxide is particularly useful in the emergency department because it does not require intravenous access and has a rapid onset of action (<5 minutes) and recovery (<5 minutes). There are no reports of adverse cardiopulmonary events, but minor side effects, including vomiting, dizziness and headache, occur in 6% to 30% of patients. The authors use a relatively inexpensive, in-house-constructed, continous-flow system, with an alarmed nitrous oxide-oxygen blender and in-wall suction/gas scavenging, to provide sedation for children undergoing suturing, intravenous cannulation, lumbar puncture, foreign body removal, burn debridement, and minor fracture reductions. Cardiorespiratory monitors, including pulse oximetry, bag-valve-mask device, oxygen, and auxiliary wall suction, should be prepared before administration, and all patients must be monitored in accordance with American Academy of pediatrics guidelines.