Is laughing gas (nitros oxide or something like that) harmful? I have a friend who's dad is a dentist and has an office next to her house. She and some of my friends have gone down there and used the laughing gas to kind of get high like with drugs but not as bad. They say it just makes them really happy but they had a party one time and guys and girls were using it and one of the girls passed out but then she was OK later. I heard a bunch of guys say they are going to do it again. Is this dangerous?