Gas anesthesia is a medical technique that uses inhaled gases to induce a state of unconsciousness and pain relief during surgical procedures. Common gases used include nitrous oxide and halothane, which work by affecting the brain's ability to process pain and awareness. This method allows patients to undergo surgery without feeling discomfort. During the procedure, the patient breathes in the anesthetic gas through a mask or breathing tube. The concentration of the gas can be adjusted to maintain the desired level of anesthesia. After the surgery, the gas is stopped, and the patient gradually wakes up as the effects wear off.