Patients usually develop neuropsychological sequelae after carbon monoxide poisoning. In a randomized trial, 46% of normobaric oxygen-treated poisoned patients developed cognitive sequelae 6 weeks after poisoning, and 17% and 45% suffered from affective sequelae. Other sequelae include gait and motor deficits, peripheral neuropathy, hearing loss and vestibular abnormalities, as well as dementia and psychosis, which can be permanent. Magnetic resonance imaging of the brain may reveal abnormal findings following carbon monoxide poisoning. In a prospective study of patients with carbon monoxide poisoning, brain MRI showed an increased amount of T2-weighted high signal. Although the prevalence of imaging abnormalities is unknown, one study showed basal ganglia damage and atrophy of the hippocampus and other structures in patients with carbon monoxide poisoning 24 years after poisoning. In one cohort study, approximately 6 years after poisoning, 19% of patients had cognitive problems and 37% had abnormal neurological assessments. Neuroimaging findings in patients without a history of carbon monoxide poisoning can be consistent with imaging abnormalities after carbon monoxide poisoning-such as hippocampal atrophy or white matter hyperintensities-associated with an increased risk of early cognitive decline. It is unclear whether patients with carbon monoxide poisoning are also at increased risk for early cognitive decline or Alzheimer’s disease. Patients with carbon monoxide poisoning should be medically followed up after discharge from the hospital. The degree and speed of recovery from poisoning is variable. The onset of sequelae often complicates the recovery process, and sequelae can persist or develop several weeks after poisoning and may be permanent. There is no specific treatment for the sequelae of carbon monoxide poisoning. Although data on the effectiveness of interventions for patients with carbon monoxide-related sequelae are lacking, clinical experience suggests that patients with sequelae should treat their symptoms through cognitive, psychiatric, occupational, verbal, and physical rehabilitation.