Hello Dear. Carbon dioxide is a gaseous product of the body s metabolism and is normally expelled through the lungs. Increased carbon dioxide in the body is generally caused by hypoventilation (that is problem in breathing), lung disease and patients with decreased consciousness. It can also occur due to increased exposure to smoke. The main treatment is treating the underlying cause of the condition, avoid going to places with lot of smoke, learn breathing exercise, avoid smoking. Oxygen can be given if the blood levels of carbon dioxide is high. Hope i have answered your question. Feel free to contact me if you have any more questions. I ll be glad to help you. All the best With warm regards Dr Sanjay Kini