Common symptoms of carbon monoxide poisoning include a dull headache, weakness or dizziness, nausea or vomiting, shortness of breath and blurred vision, according to Mayo Clinic. More severe symptoms may include confusion or loss of consciousness. The symptoms may start out subtle.
The symptoms of carbon monoxide poisoning often fit the description of flu-like symptoms, notes the Centers for Disease Control and Prevention. People who are intoxicated or sleeping often won't experience or notice the symptoms of carbon monoxide in time. If the individual doesn't get to an area with fresh air, she may pass out and eventually die. Anyone suspecting carbon monoxide poisoning should leave the area and get to fresh air before seeking medical care, warns Mayo Clinic.