The present invention is a system for administering nitrous oxide. The system includes an adjustable post mechanism attached to a dental chair. A mounting surface structure includes a top surface and a bottom surface. The bottom surface of the mounting surface structure attached to a top end of the adjustable post mechanism. A fluid control system for controlling the flow of nitrous oxide and oxygen is attached to the mounting surface structure. A nitrous oxide and oxygen supply, vacuum source, a breather bag, and a nasal delivery interface system are fluidly connected to the fluid control system and a patient. The breather bag is vertically mounted to a top surface of the mounting surface structure. In operation, the present invention provides a system for administering anesthesia/analgesia gas which provides convenient and direct access to a medical practitioner.