Laughing gas is used in relative analgesia. Dentist were the first to introduce the use of nitrous oxide in medicine for extractions. In dental procedures, patients who are tense or anxious can be administered laughing gas whereby they feel less tense and anxious about the dental procedure (anxiolytic effect).
It is also able to numb sensation to a slight extent (analgesic effect), which explains for its use for woman during childbirth. Although patients using laughing gas can still feel some sensation, they are less affected by the dis-comfort.