Nitrous oxide, more commonly known as "laughing gas," is often used as an anxiolytic agent during a dental visit. The gas is administered with a mixture of oxygen and has a calming effect that helps phobic or anxious patients relax during their dental treatment. After treatment, the nitrous is turned off and oxygen is administered for 5-10 minutes to help flush any remaining gas. The effects wear off almost immediately. Nitrous oxide rarely has side effects, although some patients may experience minor nausea.