Entonox is nothing else but LAUGHING GAS PLUS OXYGEN, GAS 'N AIR, 50% Nitrous Oxide (N2O) plus 50% Oxygen) and it was discovered over 200 years ago - has been used as an analgetic (=pain relief) for ages .... People dont know that strictly spoken it DOES NOT make you laugh (really), IT IS EUPHORIA, the extrem feeling of "happiness" that gets people to laugh plus the experience (halluzinations via sound and images). Only in the UK it is used on EVERY frontline Emergency Ambulance and in EVERY maternity department. In Germany, Switzerland, Austria and Holland for example it was taken off the market decades ago !!! Because of two reasons: It is scientifically proven that it can damage blood cells and deprive the body of Vitamin B12 and while it was used as an anasthetic during operations (e.g. at the dentist) people did die due to complications in the CO2/oxygen balance. Last but not least England (UK) is absolutely crap at looking after the environment!! In Germany for example ENTONOX is NOT used by any medical institution (neither ambulance services nor maternity units). It is forbidden, among other things because nitrous oxide is partly responsible for the GREENHOUSE EFFEKT !!! In Germany, Switzerland or Austria no woman in labour will be offered ENTONOX.... Partly because of the reasons above, partly because there are more effective analgetics AND the experience BIRTH should be kept "natural" and doesn't need to be experienced stoned and high on GAS, it is simply primitive and to be honest: it doesnt look professional, does it!!! I know paramedics in England think it is great stuff but as a matter of fact, it is antique, primitive "giggle gas" that is only used by "pseudo"-junkies and teenagers at the 15th birthday (the same kind of kiddies that think inhaling helium is funny), Didnt know you were an Entonox-junkie though :-) I'm shocked.....