Although labor epidural remains the gold standard for labor analgesia, some patients may opt for a trial of a less invasive analgesic agent. While IV/IM narcotics are an option, others may prefer a trial of nitrous oxide (N2O). In this episode, we will review the crazy history of this useful inhalational agent, and how it has ties to the manufacturing of the Colt45 handgun, how it transformed dentistry, and review the contribution to medicine by Dr. Horace Wells. We will review N2O's current application in obstetrics, and summarize statements from the ACNM and the ACOG. And…What does this gas have to do with vitamin B12? Are there any safety warnings out there regarding its use? And does it even work? Let’s answer these questions, and more, in this episode.