Abstract: An apparatus (100) and a method for subcutaneous delivery of gas for therapeutic purposes, in particular carbon dioxide (CO2), are described. The apparatus (100) includes a tank (10) for gas delivery connected, by a delivery line (20), to a needle (4) designed to be inserted into the patient's subcutaneous tissue. The apparatus further includes a heating/sterilizing system (30) disposed in the delivery line (20), upstream of the injection needle (4), to sterilize the gas and heat it to an optimal temperature to enable it to be injected beneath the patient's skin.