yea its nitrous oxide. you cant die or overdose on it, you can pass out if you do say 3 cartridges in 1 balloon at once.
you can also do it out of any whipped cream bottle. right when you open it you push but dont tilt it, so that only the nitrous comes out and not the cream.
it will hit you right away. its a rush of happiness through your entire body. it only lasts a minute or so though... to me its not worth it, but i geuss try it out if u want. its just like a minute of ecstacy