Nitrous oxide (`N_2O` ) has been used as an anesthetic and analgesic compund in surgery and dentistry. It is commonly called as the "laughing gas" because of the above properties. It has been allowed for reacreational uses also, sometimes in parties.
But the use of nitrous oxide by a patient on his own cannot be recommended. This is due to the fact that despite the anesthetic and analgesic properties of `N_2O` , there are some side effects. It can reduce the mental performance and audiovisual ability. If someone is exposed over the limit for longterm vitamin B12 deficiency can occur. Also it can have bad reproductive side effects in preganant women.
Therefore it is not wise to use `N_2O` by a patient on his own. Also only medical personnel are allowed to keep stocks of `N_2O` in most of the countries.