Poisoning by carbon monoxide from burning charcoal has become one of the popular and lethal ways of attempting suicide in Hong Kong. Survivors of the carbon monoxide poisoning often face acute and delayed adverse problems in both their physical and mental health. We report two cases of delayed onset neuropsychiatric complications caused by carbon monoxide poisoning from burning charcoal. These symptoms were characterised by a latent period, followed by an abrupt and profound deterioration in the neurocognitive function with a seemingly reversible course. The literature is reviewed regarding the aetiology, pathophysiology, and management of this condition. Regular monitoring of their neurocognitive function and forewarning of this potential complication to the survivors of carbon monoxide poisoning and their families should be essential.