Carbon dioxide is the fourth most abundant gas in the earth's atmosphere, and it is widely used in the chemical industry. Solid carbon dioxide is commonly known as dry ice. At low concentration, carbon dioxide appears to have little toxicological effect. At higher concentrations, however, it can produce an increased respiratory rate, tachycardia, cardiac arrhythmia, loss of consciousness, convulsion, and even death. Management of carbon dioxide poisoning requires the immediate removal of an individual from the toxic environment and administration of oxygen. It is important to know the concentration of carbon dioxide to which a patient has been exposed. We report a case of acute poisoning from solid carbon dioxide in a patient presenting with drowsiness and diminished mental capacity when she arrived in the emergency department. She recovered completely after administration of oxygen with conservative treatment.