Nitrous oxide has been used in anesthetic practice for nearly 170 years, longer than any other anesthetic agent. It has withstood the test of time despite its critics. In the pioneering days of anesthesia, nitrous oxide general anesthesia, using the primary and secondary saturation technique described by Dr Fred Clement, was by far best suited for ambulatory office dental surgery compared to diethyl ether and chloroform. Induction of ether anesthesia was slow and unpleasant, its recovery was prolonged, and it was explosive. Chloroform induction was somewhat more pleasant and faster than ether, but recovery was still slow and sudden cardiac